Choline, lifting heavy, and preeclampsia

Welcome to the weekly ZIP - your Zenith Informed Pregnancy!

Read on for a quick zip through 3 of the week’s most popular pregnancy questions, and the evidence behind them. Plus - bonus content on the latest & greatest in the world of pregnancy research. 

This week's top pregnancy questions:

1️⃣ Can I keep lifting weights?

2️⃣ What actually causes preeclampsia to develop?

3️⃣ Pros & cons of choline supplementation?

Can I keep lifting weights?

Staying active and keeping up with a beloved workout routine or daily movement ritual is a big priority for lots of moms! It’s no surprise that questions about lifting heavy, safe limits, and modifications to strength training are popular – especially when many women have historically been told to avoid it.

📚The tl;dr from the evidence: There’s no single “maximum” safe amount of weight to lift, or universal weightlifting guidance – it’s generally based on your individual baseline of pre-pregnancy activity. It's always important to listen to your body and  adjust as needed for safety and comfort, as hormones can increase joint flexibility and change your balance as pregnancy progresses - but research supports moderate-intensity strength training as safe for most previously active women without medical complications.

In fact, some data suggest added benefits– from improved mood and less physical discomfort during pregnancy, to potentially reduced risk of conditions like gestational diabetes or postpartum depression. 

Interestingly, while some newer studies focus on athletics, a bulk of the research that has been done on this topic is actually focused on workplace safety in roles requiring repeated manual lifting (in sometimes awkward positions). While important, the takeaways aren’t perfectly applicable to fitness where your form is different, the loads are different (and controllable), and you can design breaks/modifications easily. The good news is that lots more research is happening on exercise specifically, so more evidence to come – and a recent study found that continuing moderate to relatively heavy lifting did not increase risk of pregnancy complications. 

👀 Read Penny’s full summary of the evidence for more on strength training and weights

What actually causes preeclampsia to develop?

We’ve all heard the exasperating and anxiety-inducing pregnancy advice - “that’s normal in pregnancy… until it’s not, and then it’s an emergency.” Preeclampsia is one of the reasons for this, as early symptoms can be seemingly innocuous like swelling, headaches, or abdominal pain. Especially frustrating? While there are some known risk factors, it can also affect moms with no risk factors at all - so what is actually happening in the body, and can it be prevented?

📚The tl;dr from the evidence:  There’s still no complete answer. Preeclampsia is complex, and researchers are still unraveling the exact pathways involved, but existing research suggests it begins in the placenta. In healthy pregnancies, new blood vessels form to increase blood flow to the placenta. In preeclampsia, those vessels don’t form or function properly, creating placental stress (low oxygen) that triggers inflammation and changes in the mother’s bloodstream, in turn leading to high blood pressure and protein in the urine. 

Even without classic risk factors (like prior preeclampsia, family history, diabetes, autoimmune conditions, etc.), these vascular and placental changes can still happen – potentially due to genetic differences, random variation, immune factors, or environmental factors. More research is needed to fully understand why and when preeclampsia can happen.

And a promising start from the ongoing research: earlier this year, a paper was published in Nature looking at a racially, ethnically and geographically diverse group of women. Researchers found that a placental gene (PAPPA2) can strongly predict the most severe forms of preeclampsia without pre-existing risk factors, months before symptoms. This is huge news - this type of insight could open the door to earlier detection and proactive, tailored care for moms.

👀 Read Penny’s full summary of the evidence for more on preeclampsia and how it happens

Pros & cons of choline supplementation?

Most moms have heard about the importance of folic acid in a prenatal vitamin, but another lesser-known nutrient, choline, is increasingly getting attention. It hasn’t historically been included in meaningful amounts in most prenatal vitamins, so is there data supporting the benefit of added supplementation?

📚The tl;dr from the evidence: Choline plays a key role in fetal brain development and may help reduce the risk of certain birth defects (like neural tube defects), and some research even shows longer term cognitive and memory benefits in children into school age. This evidence is quite promising, but isn’t yet definitive (for example, there’s still some uncertainty on the optimal choline intake leading to these benefits). The research is still emerging, especially given that the AMA only began recommending choline in prenatal vitamins in 2017. 

Choline is found naturally in foods like chicken, beef, eggs, milk, soy products, and peanuts, so it’s possible to get enough through your diet. However, research has shown that a majority of pregnant women in the U.S. don’t hit the recommended 450mg/day from their diet/food alone (especially those who avoid animal products with vegan or vegetarian diets). 

Supplementation can help fill in the gap, and no evidence of harm has been observed at the recommended doses, so long as the upper limit of 3,500 mg/day isn’t exceeded (for reference, one large egg yolk contains about 125 mg of choline). Some prenatals now do include choline, or standalone choline supplements are available as well. As with any supplement, look for options that are independently tested for purity and potency, and produced by reputable brands.

👀 Read Penny’s full summary of the evidence for more on choline

🤓 Zenith's top read of the week

Bonus: what the Zenith team found interesting this week. Think cool pregnancy research or recently published studies, news in pregnancy health and policy, and more!

Prescribed opioid analgesic use in pregnancy and risk of neurodevelopmental disorders in children: A retrospective study in Sweden (Emma Cleary et al, PLOS Medicine) - Pain is unfortunately quite common in pregnancy, yet it’s unclear whether exposure to commonly prescribed opioid medications (like oxycodone or morphine) can increase risk of autism or ADHD in children. This new study leveraged a large (1.2+ million) cohort of births from Sweden to examine that link and compare to previously observed associations..

What they found? Accounting for differences in background characteristics between children with/without opioid exposure from pregnancy, they observed that the associations with autism/ADHD were either substantially weakened or no longer present. 

This study is exciting because of the unique design. The researchers employed multiple approaches to control for the confounding factors that might affect both the likelihood someone is prescribed an opioid during pregnancy, and the likelihood of their child having ADHD or autism. While there’s still a lot left to learn (such as the impact of high doses or durations), it’s promising to see the evidence evolving to refine the risks & benefits of different pain management options for pregnant moms, and to ultimately help deliver better evidence-based care. 

P.S.: We've recently covered both this study and why so many good pregnancy studies are coming from Sweden on social media; follow along on Instagram and TikTok (@thezenithhealth)!

Key excerpt:

“At the population level, we replicated previous findings showing that risk of neurodevelopmental disorders increases as the dose, duration, and number of prescriptions increases. 

However, when we combined statistical controls for a wide range of parental and familial factors with the design comparing to children whose birthing parent received [prescribed opioid analgesics] (POAs) before but not during pregnancy and the sibling comparison, we found that the associations between the majority of indexes of POA exposure and both ASD and ADHD were largely attenuated and did not differ statistically from the null…. Therefore, these results suggest that confounding may largely account for the excess risk for ASD and ADHD observed in children exposed to prenatal POAs at the levels prescribed in our cohort.”