Tag: pregnancy complications

Hyperemesis Gravida Linked to Pregnancy, Birth Complications

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Pregnant women with a severe form of nausea face increased risks for several pregnancy and birth complications, according to a new Stanford Medicine study of 2.5 million California births.

The research, published in the American Journal of Epidemiology, is the first large, US population-based study of the dangers of severe pregnancy nausea and vomiting, a condition formally known as hyperemesis gravidarum, or HG.

While most pregnant women – 70% to 80% – experience some nausea, it usually leaves no lasting effects. In contrast, as the new research shows, HG puts a major strain on the 1% to 3% of the pregnancies affected.

“Hyperemesis gravidarum is not just bad morning sickness; it’s severe enough to cause dehydration and significant weight loss,” said lead study author Rebecca Gardner, a Stanford Medicine graduate student in epidemiology and clinical research.

The study’s senior authors are Julia Fridman Simard, ScD, associate professor of epidemiology and population health and of immunology and rheumatology, and Gary Shaw, DrPH, the Rosemarie Hess Professor and a professor of pediatrics.

The research team looked at complications in pregnancies in which the mother was hospitalised for HG, compared with pregnancies without such hospitalisations.

“We found hyperemesis gravidarum was linked to higher risk for preterm birth, anaemia, smaller-than-expected babies, preeclampsia, gestational hypertension and placental abruption,” Gardner said. “Hospitalization for HG really does flag a pregnancy as being at higher risk for a range of serious complications.”

Struggling to get nourishment

Pregnant women with HG experience severe, sustained nausea and vomiting, often continuing throughout their pregnancies. They struggle to eat; stay hydrated; and absorb enough nutrients that play key roles in early pregnancy, such as folate. (Adequate folate intake reduces the risk of certain birth defects.) Women with HG can lose a lot of weight at a time when they should be gaining; one study found that about a quarter of HG patients lost more than 15% of their pre-pregnancy weight.

“We know from other studies that women with HG don’t get as many nutrients,” Gardner said. “This could impair placental development, which we think leads to higher risk for some of the outcomes we looked for, such as preeclampsia and babies being smaller than expected at birth.”

But previous studies examining potential links between HG and poor pregnancy outcomes had weaknesses, Gardner said: Many were small, and nearly all used data from European countries with populations that are less diverse than the U.S. population and that have medical systems structured differently from the U.S. system.

The study examined records for single-baby California births from 2007 to 2011. The researchers had access to demographic information about mothers, pre-pregnancy body mass index and census tract data that was used to calculate each patient’s level of social vulnerability. The researchers also had access to diagnostic codes from patients’ pregnancy and birth medical records.

Of the 2 476 492 births included in the final analysis, 53,681, or 2.2%, were to mothers with HG, meaning they received emergency department or hospital inpatient care for hyperemesis gravidarum.  

Compared with those who were never hospitalised for HG, women with HG had higher risk for preeclampsia, a pregnancy complication that can cause seizures if untreated; gestational hypertension, or high blood pressure in pregnancy; preterm birth, meaning delivery three or more weeks before the due date; babies that were small for their gestational age, meaning they had grown less than expected during foetal development, anaemia, and placental abruption, in which the placenta becomes partly or completely detached from the uterus before delivery.

The increase in relative risk for each complication varied. For instance, after adjusting for possible confounding factors, women with HG were about 18% more likely to have preeclampsia, about 25% more likely to deliver early, about 37% more likely to be anaemic and about 14% more likely to experience a placental abruption than women without HG.

Women who were first hospitalised for HG during the second trimester of pregnancy were more likely to experience complications than those hospitalised during the first trimester, the study found.

A flag for closer monitoring

Guidelines from the American College of Obstetricians and Gynecologists for treating HG changed in 2018, after the data used for this study was collected, Gardner noted. The guidelines now encourage treating pregnancy nausea faster and more aggressively, and two medications are now approved by the US Food and Drug Administration for nausea and vomiting in pregnancy. More research could help clarify the effects of these newer guidelines, Gardner said.

More research could also show whether HG should prompt physicians to offer additional preventive care, such as low-dose aspirin, which is already used to prevent preeclampsia in patients who are at risk for other reasons.

The research team hopes that its findings will motivate physicians and pregnant women to pay closer attention to HG.

“For physicians, I think this data means that pregnancies with HG hospitalisation may warrant closer monitoring for certain complications,” Gardner said.

“Pregnant women need to know that most HG pregnancies still result in healthy outcomes for the mom and baby, but HG does need to be taken seriously,” she said. It’s important to advocate for yourself by asking your doctor if you need more monitoring or anti-nausea medication, Gardner said, adding, “This is not just something to push through.”

Source: Stanford Medicine

Iodine Deficiency Is Creeping Back. Vegans, Vegetarians and Pregnant Women Are Most at Risk

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José Miguel Soriano del Castillo, Universitat de València

Iodine deficiency is often seen as a problem of the past, but this isn’t entirely true. During the 20th century, the iodisation of salt became one of the most effective public health interventions for preventing conditions caused by a lack of this mineral, including goiter (enlargement of the thyroid gland) and preventable damage to neurological development.

The World Health Organization (WHO) still views iodised salt as a safe and effective strategy, while UNICEF notes that it is the most widely used way of improving iodine intake worldwide.

However, the success of this simple measure means iodine has all but disappeared from public debate. And today, in several countries, signs of insufficient intake are once again being detected in certain groups, particularly in pregnant or breastfeeding women and people on restrictive or poorly planned diets.

What we are witnessing is not a dramatic resurgence of the most severe symptoms everywhere, but rather a silent risk of deficiency in contexts where vigilance has waned.

Iodine’s role in the body

Iodine is an essential micronutrient for the synthesis of thyroxine (T4) and triiodothyronine (T3), hormones that regulate metabolism, growth, and many physiological processes. Adequate intake during pregnancy and early childhood is particularly important for the normal development of the central nervous system and for the early stages of brain maturation.

In addition, the body’s needs increase during pregnancy and breastfeeding due to increased maternal production of thyroid hormones, greater renal excretion of iodine, and the transfer of this mineral to the fetus and the infant.

Why deficiency is on the rise again

The issue is not that people have stopped consuming salt, but rather that the type of salt they consume has changed, as have the sources of sodium in their diet. In recent years, iodised salt has been replaced in many households by “gourmet” or “natural” salts. These include sea salt, pink Himalayan salt, flaked salt and kosher salt, which are often perceived as more sophisticated or healthier, even though they are not always iodised.

In a way, iodised salt has an image problem. Compared to the culinary prestige of its trendy rivals, it has come to be viewed as something ordinary, outdated even.

Today, lot of our salt intake also comes from processed and ultraprocessed foods, meaning the use of iodised salt cannot be guaranteed. For this reason, the World Health Organization has called for coordination between policies that aim to reduce sodium intake and those that promote iodised salt.

The makeup of our diets has also changed a lot. Iodine is naturally present in all seafood, some dairy products and in eggs, though the quantity may vary from one region or food system to another. When a person reduces or cuts out several of these sources at once while not also consuming iodised salt or fortified foods, the risk of deficiency increases.

The result is that a basic, inexpensive, and effective micronutrient has fallen out of the spotlight just as certain groups are once again at risk of not getting enough iodine.

Plant-based diets

Vegetarian and vegan diets can be healthy, but they must take iodine into consideration. A 2023 review in the British Journal of Nutrition concluded that people following a plant-based diet, especially vegans, may find it hard to get the recommended amount of iodine from these foods alone.

This does not mean a plant-based diet is inherently lacking – and the solution is straightforward. Just as vitamin B12 is is commonly recommended for those who reduce their consumption of fish or dairy – or when people replace animal products with unfortified plant-based alternatives – so too should iodine.

Pregnancy and breastfeeding

Iodine deserves special attention during pregnancy. There is strong evidence that a severe deficiency of this micronutrient can affect fetal development and thyroid function, which is why many organisations use specific thresholds to assess iodine status in pregnant women. The US National Institutes of Health states that a urinary concentration of 150–249 micrograms per liter (μg/L) in pregnant women is considered adequate for the general population.

But there is a caveat to this. Concerns about mild or moderate deficiency are legitimate, but there is no conclusive evidence as to the cognitive benefits of supplementing all pregnant women who show a mild deficiency. Reviews and trials have indicated that there is plausible biological concern, and some studies suggest an association with poorer outcomes, but controlled experiments have not unanimously shown clear improvements in infant neurodevelopment.

Nevertheless, several scientific societies have adopted a cautious stance. The American Thyroid Association, for instance, states that women who are planning to conceive, pregnant or breastfeeding should receive 150 μg of iodine daily in prenatal or multivitamin supplements, usually in the form of potassium iodide, to help meet increased requirements.

Why ‘more salt’ is not the answer

Another important clarification is needed here. Advocating for iodised salt does not mean recommending a higher salt intake. The WHO maintains its recommendation to reduce sodium intake due to its link with high blood pressure and cardiovascular disease. In terms of public health, the solution is not “more salt”, but less – though the salt we do eat should be iodised.

In fact, the WHO itself has emphasised that reducing salt intake and fortifying salt with iodine are compatible, provided the concentration of the mineral is properly adjusted and salt used by the food industry is also fortified.

This point is key because it avoids two common pitfalls: turning the issue into a nostalgic defence of table salt, or the other extreme of assuming that any reduction in sodium intake will automatically solve all health problems without any nutritional consequences. But it is possible to strike a balance between preventing cardiovascular disease and iodine deficiency.

José Miguel Soriano del Castillo, Catedrático de Nutrición y Bromatología del Departamento de Medicina Preventiva y Salud Pública, Universitat de València

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Tranexamic Acid Prevents Severe Bleeding in Caesarean Births

New trial adds high quality evidence on benefits of tranexamic acid for high-risk women

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Giving tranexamic acid to women with placenta praevia (when the placenta covers the cervical opening) undergoing caesarean birth leads to a significant yet modest reduction in severe bleeding after delivery with no evidence of an increase in serious adverse events, finds a trial from China published by The BMJ today.

Tranexamic acid is widely used to prevent or reduce heavy bleeding usually after surgery or trauma. It works by inhibiting blood clot breakdown and is recommended for the treatment of severe bleeding after childbirth (postpartum haemorrhage).

But high quality evidence on its prophylactic use to prevent postpartum haemorrhage in high risk women remains scarce.

To address this gap, researchers in China set out to examine the effect of tranexamic acid in women with placenta praevia, a group at high risk of severe bleeding.

The trial included 1694 pregnant women with placenta praevia who were scheduled for caesarean delivery at 24 maternity units across China between July 2023 and March 2025.

Participants received prophylactic oxytocin – standard treatment to reduce blood loss after delivery – and were randomly assigned to receive either intravenous tranexamic acid (845 women) or placebo (849 women) over 10 minutes, starting within five minutes of umbilical cord clamping.

The main outcome measure was postpartum haemorrhage, defined as blood loss of at least 1000 mL or red blood cell transfusion within two days after delivery. Serious adverse events including blood clots, seizures, acute kidney or liver injury, and maternal death, were also recorded.

The results show that prophylactic tranexamic acid reduced the rate of postpartum haemorrhage by 15%, from 35.1% to 29.7% compared with placebo. This means that for every 19 women receiving prophylactic tranexamic acid, one case of postpartum haemorrhage would be prevented.

Rates of serious adverse effects were similar between the two groups.

The researchers acknowledge various limitations including that the findings are specific to women with placenta praevia receiving prophylactic oxytocin and therefore may not apply to other obstetric populations. However, this was a well-designed trial and results were consistent after further analyses, suggesting that the findings are robust.

As such, they conclude: “In a high risk population – specifically, women with placenta praevia undergoing caesarean delivery – prophylactic tranexamic acid leads to a statistically significant but modest reduction in the incidence of postpartum haemorrhage.”

“Future studies in diverse international settings are warranted to validate these results and to identify specific patient subgroups most likely to benefit from prophylactic use of tranexamic acid,” they add.

In a linked editorial, UK researchers point out that this modest reduction in bleeding understates the impact, particularly in women at high risk of harm from bleeding, for whom even modest relative risk reductions translate into worthwhile benefits.

The focus should now shift from whether tranexamic acid reduces bleeding to how it is used to maximise patient benefit, they say, noting that in non-obstetric surgery, tranexamic acid is given before incision, but in caesarean section trials it is delayed until after cord clamping to avoid placental transfer.

They recommend evaluating pre-incision administration for caesarean section, while carefully monitoring maternal and neonatal outcomes.

Source: The BMJ Group

More Evidence Tying Epilepsy Drugs in Pregnancy to Developmental Risks

Study adds weight to previously reported risks and calls for monitoring of new antiseizure drugs

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Findings published by The BMJ reinforce previous research linking use of the antiseizure drug valproate during pregnancy to neurodevelopmental disorders such as ADHD and autism in children, and indicate no substantial risk for several other antiseizure drugs including levetiracetam and lamotrigine.

However, the researchers say continued monitoring of the few signals – possible associations between a medicine and an unintended side effect – that emerged (eg, for zonisamide) will be important.

Antiseizure drugs are commonly and increasingly used by women of childbearing age for conditions like epilepsy, bipolar disorders, and migraine prevention. Women with epilepsy are advised to continue taking these during pregnancy, as uncontrolled seizures pose risks to both mother and child.

Yet, while valproate use during pregnancy has been linked to impaired neurodevelopment in children, information on other antiseizure drugs is limited.

To address this gap, researchers analysed claims data for pregnancies with diagnosed epilepsy from two large US public and commercial insurance databases, spanning the period from 2000 to 2021.

They compared 14,993 children exposed to at least one antiseizure medication during the second half of pregnancy with 8,887 unexposed children. Of these, 5,505 were followed for at least 5 years and 2,516 for at least 8 years after birth.

Potentially influential factors including mother’s age, ethnicity, mental health, substance use, other medication use and underlying conditions were also taken into account.

Valproate and zonisamide showed associations with several neurodevelopmental disorders, whereas levetiracetam and phenytoin were not associated with an increased risk of any of the studied outcomes.

Although no meaningful associations were found for topiramate and lamotrigine across most outcomes, there was a potential signal for intellectual disability (both drugs) and learning difficulty (topiramate only). However, the authors note that  these findings are based on small numbers and require confirmation in follow-up studies.

Several other drugs were also associated with a risk increase for intellectual disability. However, the authors note that these estimates are based on small numbers and therefore should be interpreted with caution.

Carbamazepine and oxcarbazepine also showed a modest risk increase for ADHD and behavioral disorders.

This is an observational study, so no definitive conclusions can be drawn about cause and effect, and the authors point to several limitations including relying on insurance claims data and the potential influence of other unmeasured factors such as underlying epilepsy type and severity.

However, the use of two large nationwide databases of insured pregnant women linked to their children enhanced the generalisability of their findings and enabled them to assess the risk of specific neurodevelopmental disorders associated with individual antiseizure medications. Results were also consistent after additional analyses, suggesting that they are robust.

As such, they conclude: “Our study reinforces the substantial risks of neurodevelopmental disorders associated with prenatal valproate exposure and suggests the need to further evaluate the safety of zonisamide during pregnancy.”

“Continued monitoring of newer antiseizure drugs and the few potential signals that emerged (ie, the moderate increased risk of ADHD and behavioural disorder after carbamazepine and oxcarbazepine exposure, and the association of several antiseizure drugs with intellectual disability) will be important,” they add.

Source: BMJ Group

Uneven Adherence to Magnesium Sulfate, Steroids in High-risk Pregnancies

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Prenatal magnesium sulfate and steroids can reduce the risks of cerebral palsy and respiratory complications in preterm infants. A review in the International Journal of Gynecology & Obstetrics found that despite being recommended internationally for pregnant women at risk of preterm delivery, these medications are used variably between and within countries.

When they analysed 2012–2024 information on 45 619 babies born at 24–32 weeks’ gestation at 1111 hospitals in an international network, along with information from the UK National Neonatal Research Database and a literature review, investigators found that on average, less than half of infants had been exposed to preterm magnesium sulfate in middle-income countries, and approximately three-quarters in high-income countries. Even within high-income countries, there were large discrepancies in care. Preterm steroids were used more frequently with less variation, although treatment gaps were still apparent.

“Our study has highlighted the international disparities in how two key treatments to protect pre-term babies are implemented. These gaps aren’t because of a lack of evidence,” said corresponding author Hannah B. Edwards, MA, MSc, of the University of Bristol, in the UK. “Lessons can be learned from successful implementation programs like PReCePT, which has transformed use of magnesium sulphate in pre-term births in England. The bigger-picture goal should now be to ensure that no matter where a baby is born, their mother has access to the evidence-based treatments that offer the best start in life.”

Source: Wiley

Virtual Antenatal Care Linked to Poorer Pregnancy Outcomes

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Women who receive more virtual antenatal care during their second or third trimesters could experience poorer pregnancy outcomes, including higher risks of preterm birth, Caesarean sections and neonatal intensive care unit admissions, a new study suggests.

Increased virtual antenatal care in later pregnancy was also found to be associated with lower rates of early skin-to-skin contact with the newborn and fewer instances of breastfeeding as the first feed.

Led by King’s College London and published in the American Journal of Obstetrics & Gynecology, the study looked at associations between virtual antenatal care and pregnancy outcomes in more than 34 000 pregnancies from a diverse, South London population, from periods before and during the COVID-19 pandemic.

Women were split into four groups, according to the proportion of virtual antenatal care appointments received during their pregnancy – low and stable virtual antenatal care throughout pregnancy, high first trimester virtual antenatal care, high second trimester virtual antenatal care, and high third trimester virtual antenatal care.

Pregnancy and birth outcome data were obtained from hospital records via the Early Life Cross-Linkage in Research, Born in South London (eLIXIR-BiSL) platform, funded by the UKRI Medical Research Council (MRC).

Analyses of the data revealed that, compared with those who received a low and stable proportion of virtual antenatal care throughout their pregnancy:

  • Women who received a high proportion of virtual antenatal care in their second trimester experienced more premature births (before 37 weeks), labour inductions, breech presentation, and bleeding after birth; and
  • Women who received a high proportion of virtual antenatal care in their third trimester had more premature births (before 37 weeks), elective or emergency Caesarean sections, and neonatal intensive care unit admissions; as well as lower rates of third- or fourth-degree vaginal tears, early skin-to-skin contact with the newborn and fewer instances of breastfeeding as the first feed.

During the COVID-19 pandemic, the use of virtual antenatal care increased, to limit face-to-face contact and prevent spread of the SARS-CoV-2 virus. While research has looked at the experiences of women and healthcare providers receiving and delivering virtual care, fewer studies have focused on the impact of virtual antenatal care on pregnancy outcomes.

Our work adds an important perspective to the growing evidence base on virtual antenatal care, suggesting that the timing of its use during pregnancy may influence pregnancy outcomes.

Dr Katie Dalrymple, Lecturer at King’s and first author of the study

The findings build on an earlier study by the team, which found that virtual maternity care during the COVID-19 pandemic was linked to higher NHS costs – with each 1% increase in virtual antenatal care associated with a £7 increase in maternity costs to the NHS.

In addition to the cost implications of virtual care, the findings from the new study suggest that virtual antenatal care could come with increased risks to mother and baby. The authors conclude that careful consideration may be needed to minimise these risks before using virtual antenatal care in future health system shocks or to replace face-to-face care.

Our study findings suggest the need for careful integration of virtual care in maternity services, to minimise potential risks.

Professor Laura Magee, Professor of Women’s Health at King’s and co-senior author of the paper

Source: King’s College London

Pre-pregnancy Hypoglycaemia Linked with Higher Risk of Preterm Birth, Other Risks

In study of nearly 5 million Chinese women, these links varied according to body mass index

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An analysis of data from more than 4.7 million Chinese women showed that those who had low blood sugar levels prior to conception were more likely to have certain adverse pregnancy outcomes – such as their baby being born preterm or with low birth weight. Hanbin Wu of the Chinese University of Hong Kong, in collaboration with the National Research Institute for Family Planning, presents these findings on July 29th in the open-access journal PLOS Medicine.

Prior research has shown that women who are hyperglycaemic before or during pregnancy are more likely to face adverse pregnancy outcomes, as are women who are hypoglycaemic during pregnancy.

However, few studies have explored whether hypoglycaemia detected before pregnancy is associated with adverse pregnancy outcomes for women without pre-existing diabetes. To help clarify, Wu and colleagues retrospectively analysed data on 4 866 919 Chinese women from the National Free Preconception Checkup Project, a free health service for women planning to conceive. Using data from 2013 to 2016, they analysed associations between preconception hypoglycaemia and pregnancy outcomes.

A total of 239 128 of the women had preconception hypoglycaemia. Compared to those with normal preconception blood sugar, they had a higher risk of certain adverse pregnancy outcomes, such as preterm birth, low birth weight, or birth defects. Women with hypoglycaemia tended to be younger than those with normal blood sugar levels and were more likely to have BMIs in the “underweight” category.

However, the adverse pregnancy risks associated with preconception hypoglycaemia varied for women with different BMIs. For instance, underweight women had a higher risk of miscarriage, while overweight women had a lower risk of their baby being large for their gestational age.

On the basis of these findings, the researchers suggest that screening for preconception hypoglycemia could be explored for its potential to improve pregnancy outcomes. Further research could also address some limitations of this study, such as by including women from other countries and more information on patients’ gestational complications.

The authors state, “In addition to paying attention to women with preconception hyperglycemia, our findings call for increased concern for women with hypoglycemia in preconception glycemic screening. These findings emphasize the importance of preconception examination in preventing and managing reproductive health risks for all women planning to conceive, and also highlight the necessity of comprehensive screening and coordinated interventions for abnormal FPG (fasting plasma glucose) prior to and during pregnancy, which is crucial for advancing the intervention window and mitigating the risk of adverse pregnancy outcomes.”

Provided by PLOS

Antibiotics Taken During Pregnancy May Reduce Preterm Births

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A study of almost 1000 pregnant women in Zimbabwe found that a daily dose of a commonly used, safe and inexpensive antibiotic may have led to fewer babies being born early. Among women living with HIV, those who received the antibiotic had larger babies who were less likely to be preterm.

One in four live-born infants worldwide is preterm (born at 37 weeks’ gestation or before), is small for gestational age, or has a low birth weight. The mortality rate for these small and vulnerable newborns is high, with prematurity now the leading cause of death among children younger than 5 years of age. Maternal infections and inflammation during pregnancy are linked to adverse birth outcomes, particularly for babies born to mothers living with HIV, who have a greater risk of being born too small or too soon. 

An international group of researchers, led by Professor Andrew Prendergast from Queen Mary University of London, and Bernard Chasekwa from the Zvitambo Institute for Maternal and Child Health Research in Zimbabwe, conducted the Cotrimoxazole for Mothers to Improve Birthweight in Infants (COMBI) randomised controlled trial, to examine whether prescribing pregnant women a daily dose of trimethoprim–sulfamethoxazole (a broad-spectrum antimicrobial agent with anti-inflammatory properties, widely used in sub-Saharan Africa) would result in heavier birth weights, decreased premature births, and better health outcomes for their babies.  

993 pregnant women were recruited from three antenatal clinics in Shurugwi, a district in central Zimbabwe, and received either 960 mg of the drug or a placebo daily. The participants received regular antenatal care during their pregnancies and data regarding their birth outcomes were recorded. 

The study, published in the New England Journal of Medicine, found that although birthweight did not differ significantly between the two groups, the trimethoprim–sulfamethoxazole group showed a 40% reduction in the proportion of preterm births, compared to the placebo group. Overall, 6.9% of mothers receiving the drug had babies born preterm, compared to 11.5% of mothers receiving the placebo, and no women receiving antibiotics had babies born prior to 28 weeks. For babies born to a small group of 131 women with HIV, the reduction in premature births was especially marked, with only 2% of births in the trimethoprim–sulfamethoxazole group preterm, as compared with 14% in the placebo group. Babies exposed to antibiotics during pregnancy also showed a 177 gram increase in their birth weight. 

Bernard Chasekwa, first author, said: “Our trial, conducted within routine antenatal care and enrolling women predominantly from rural areas, showed that trimethoprim-sulfamethoxazole did not improve birthweight, which was our main outcome. However, there was an intriguing suggestion that it may have improved the length of pregnancy and reduced the proportion of preterm births. We now need to repeat this trial in different settings around the world to see whether antibiotics during pregnancy can help reduce the risk of prematurity.”  

Source: Queen Mary University of London

Updated Review Raises Concern About Cannabis Use in Pregnancy

Research team finds moderate risk for preterm birth, low birth weight

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An updated systematic review finds that consuming cannabis while pregnant appears to increase the odds of preterm birth, low birth weight and infant death. This study by researchers at Oregon Health & Science University appears in JAMA Pediatrics.

Study lead author Jamie Lo, MD, MCR, is a physician-scientist who provides prenatal care for high-risk pregnancies at OHSU.

“Patients are coming to me in their prenatal visits saying, ‘I quit smoking and drinking, but is it safe to still use cannabis?’” said Lo, associate professor of obstetrics and gynaecology (maternal-foetal medicine) in the OHSU School of Medicine. “Until direct harms have been proven, they perceive it to be safe to use.”

In fact, cannabis remains one of the most common substances used in pregnancy that’s still illegal under federal law, and, unlike declines in prenatal use of alcohol or nicotine, cannabis use is continuing to increase. Lo said many of her patients are reluctant to give up cannabis during pregnancy because it helps to reduce common prenatal symptoms such as nausea, insomnia and pain.

Researchers updated the systematic review and meta-analysis, drawing on a total of 51 observational studies involving 21.1 million people to examine the potential adverse effects of cannabis use in pregnancy. The researchers found eight new studies since their previous update, raising the certainty of evidence from “very-low-to-low” to “moderate” for increased odds of low birth weight, preterm birth and babies being small for their gestational age.

The updated review also indicated increased odds of newborn mortality, though still with low certainty.

Researchers noted that the new systematic review includes a larger proportion of human observational studies examining people who only use cannabis, but don’t also use nicotine. And even though the evidence is low to moderate for adverse outcomes, Lo noted that the findings are consistent with definitive evidence in nonhuman primate models exposed to THC, the main psychoactive compound in cannabis.

The related research in animal models included standard prenatal ultrasound and MRI imaging that revealed a detrimental effect on the placenta, in terms of blood flow and availability of oxygen in addition to decreased volume of amniotic fluid.

“These findings tell me as an obstetrician that the placenta is not functioning as it normally would in pregnancy,” Lo said. “When the placenta isn’t functioning well, it can affect the baby’s development and growth.”

Even though cannabis remains a Schedule 1 substance under the federal Controlled Substances Act, Oregon is one of several states that have legalised it under state law for medicinal and recreational use. Lo said she recommends a harm-reduction approach to patients. For those who cannot abstain, she advises them to reduce the amount and frequency of use to help reduce the risk of prenatal and infant complications.

“Even using less can mitigate the risk,” she said. “Abstinence is ideal, but it’s not realistic for many patients.”

Source: Oregon Health & Science University

Amniotic Fluid Protects Both Baby and Birthing Parent, Research Finds

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Researchers at Oregon Health & Science University have made new discoveries about amniotic fluid, which is historically not well understood in medical research due to the difficulty in obtaining it during pregnancy, especially across gestation in birthing parents.

In addition to providing much-needed cushion and protection for the foetus, amniotic fluid also aids in development of vital organs – especially the lungs, digestive tract and skin – and stabilises the temperature inside the womb.

The new study, published in the journal Research and Practice in Thrombosis and Haemostasis, found that the addition of amniotic fluid to plasma improves the blood’s ability to thicken and clot, which is a critical and likely a protective function throughout pregnancy and during delivery for both the birthing parent and the baby. It also appears to offer other unexpected functions, such as serving as a ‘pre-milk’ for foetuses.

The mechanism of amniotic fluid’s role in foetal development is not well understood and is understudied: The OHSU study is one of the first to identify how the features and properties of amniotic fluid change over time, especially those properties that play a role in thickening the blood, and how those changes can affect how maternal blood coagulates. If a pregnant person’s blood does not clot properly, it can create life-threatening complications for the foetus and birthing parent, including excessive bleeding during pregnancy and delivery.  

“We have always known that amniotic fluid is very important for foetal development and growth, but we don’t know much about it beyond that,” said the study’s corresponding author Jamie Lo, MD, MCR., associate professor of obstetrics and gynaecology (maternal-foetal medicine) in the OHSU School of Medicine, and Division of Reproductive & Developmental Sciences at the Oregon National Primate Research Center, or ONPRC. “We examined amniotic fluid across the pregnancy and found that indeed the composition and proteins in the amniotic fluid do change to match the growing needs of the developing baby.”

This discovery prompted Lo and her team to work with scientists in the Department of Biomedical Engineering at OHSU to take a deeper dive into the potential protective factors of amniotic fluid, and consider potential regenerative and therapeutic uses that could be developed down the road.

The research involved a multidisciplinary team including Lo, Chih Jen Yang, MD, Lyndsey Shorey-Kendrick, PhD, Joseph Shatzel, MD, MCR, Brian Scottoline, MD, PhD, and Owen McCarty, PhD.

Researchers analysed the properties of amniotic fluid obtained by amniocentesis, a prenatal test that involves sampling a small amount of amniotic fluid to examine the health of the pregnancy, from both human and non-human primates at gestational-age matched timepoints. The findings showed that amniotic fluid increases blood clotting through key fatty acids and proteins that change each trimester and help regulate coagulation.

With the untapped potential for amniotic fluid to aid in diagnosing and treating various prenatal conditions, researchers are now collaborating with Sanjay Malhotra, PhD, professor of cell, developmental and cancer biology in the OHSU School of Medicine, to target disorders of pregnancy – including disorders that affect the blood and blood-forming organs – that could benefit from the protective properties of proteins and other compounds within amniotic fluid.

Researchers are eager to learn more about the potential uses of amniotic fluid components and how they might be harnessed to improve prenatal and maternal health.

“Babies born prematurely miss out on critical weeks developing within amniotic fluid,” said the study’s co-senior author Brian Scottoline, MD, PhD, professor of paediatrics (neonatology), OHSU School of Medicine. “But if we have a better understanding of amniotic fluid, how it develops and what properties are valuable for what functions, that opens up many new possibilities for creating new therapies.”

“Through our research, our team is learning that amniotic fluid may be a critical precursor to breast milk – almost like ‘pre-term’ milk for a foetus in utero. With that analogy, could we eventually develop a formula that’s fit for preterm babies that mimics amniotic fluid, aiding in growth and development and protecting babies from complications of being born prematurely?” Lo added. “This is really the tip of the iceberg for what’s possible.”

Source: Oregon Health & Science University