Hypnobirthing, NA beer, and gestational diabetes trends

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 Rh incompatibility - what does it mean, and what can I do?

2️⃣ What’s hypnobirthing, and is it evidence-backed?

3️⃣ Can I drink nonalcoholic beer or wine?

Rh incompatibility - what does it mean, and what can I do?

Blood type testing is routine early in pregnancy, but hearing about a resulting “incompatibility” can catch moms off guard and create anxiety. Here’s what Rh incompatibility actually means, how it’s detected, and the evidence on what it means for your pregnancy and your baby. 

📚The tl;dr from the evidence: The “positive” or “negative” part of your blood type (e.g. A negative, B positive) refers to something called your Rh status – the “Rh factor” is a protein that may be present on the surface of red blood cells. If you have this protein, you’re considered “Rh positive” (and vice versa, if you don’t have it). Sometimes, mom and baby can have different Rh status, since the baby inherits genes from both parents.

If you (mom) are Rh-negative, and your baby is Rh-positive, the difference can cause your immune system to see the baby’s blood cells as foreign and trigger an antibody response if exposed (if their blood mixes with yours - during delivery or other procedures during pregnancy). This is called “Rh incompatibility,” and doesn’t usually affect your first pregnancy (as building up these antibodies takes time), but if untreated, can affect future pregnancies - potentially causing health complications for your future babies like anemia or jaundice. 

The good news? There’s a highly effective treatment for Rh-negative moms – typically an injection of RhoGAM (Rh immune globulin, which contains antibodies that stop your immune system from reacting to the Rh-positive blood cells) around 28 weeks of pregnancy, and potentially after delivery or other events/procedures, depending on your baby’s status.

This is one of the reasons why routine prenatal appointments and testing are so important - Rh incompatibility wouldn’t be symptomatic for you during pregnancy, but knowing your Rh status via the first-trimester blood test means that there are evidence-based, proven preventative approaches to help avoid preventable complications for your baby or future babies down the line.

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

What’s hypnobirthing, and is it evidence-backed?

If you’ve heard friends, TikTok influencers, or childbirth educators rave about hypnobirthing, you’re not alone - it’s been popping up everywhere! As more women look for non-medical ways to prepare for labor, interest in hypnobirthing is growing. Is it just a “woo” technique, or are there studies backing its efficacy?

📚The tl;dr from the evidence: Hypnobirthing is an approach used during birth aiming to naturally reduce pain, anxiety, and fear - using relaxation and breathing techniques as well as self-hypnosis. 

There have been studies, including randomized controlled trials, looking at the impact of hypnobirthing on both the experience and medical outcomes of labor and delivery. In general, studies have indicated that hypnobirthing can decrease levels of birth anxiety and improve satisfaction overall, but the evidence strength for clinical outcomes is mixed/inconsistent. For example, there is some evidence that there may be lower needs for interventions like medical pain relief (e.g. an epidural), but the data is inconsistent on whether that is actually always true and the overall evidence quality is moderate at best. 

The design and quality of studies looking at hypnobirthing can vary quite a bit, which makes it challenging to make definitive conclusions about its efficacy. However, it’s not harmful, and the strongest data we do have points to its psychological benefits around anxiety reduction and satisfaction - very important aspects of childbirth! - so if your interest is piqued, check out a class or instructor who can help you learn more about this approach!

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

Can I drink nonalcoholic beer or wine?

Alcohol is one topic in pregnancy where the evidence is pretty clear - drinking during pregnancy does carry risks and can lead to adverse outcomes for mom and baby. But with the recent boom in nonalcoholic spirits, beer and wine on the market, new questions have come up for moms: can I drink the NA version of my favorite beverage while pregnant? Is it truly safe?

📚The tl;dr from the evidence: The safety consideration for NA beer, wine, or spirits is whether or not the specific beverage you’re considering is truly 0.0% alcohol by volume (ABV). “Nonalcoholic” beer is legally defined as less than 0.5% ABV, so many brands do include some alcohol up to this level - and one study even tested 45 different NA beverages for alcohol content, and found that some (29%) contained more alcohol than the 0.5% threshold, up to 1% ABV in some cases.

Because there is not a large body of research focused specifically on “NA” replacement beverages in pregnancy, and we know that there is no threshold for alcohol considered to be safe, checking the labels of the beverage you’re consuming is important if you’re looking to minimize risk. Look for NA drinks that are explicitly labeled “alcohol-free” or “0.0% alcohol” for the safest option. Alternatively, mocktails (without an NA spirit) can be a safe choice as well if in doubt about the NA brands on offer. 

👀 Read Penny’s full summary of the evidence for more on NA beer and wine

🤓 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!

Gestational Diabetes Rose Every Year in the US Since 2016 (Northwestern Medicine) - Gestational diabetes is a pregnancy complication in which the mother develops diabetes (high blood sugar) without a previous diagnosis, and a new study of 12.6 million births by Northwestern researchers shows a 36 percent increase in the condition from 2016-2024. Gestational diabetes can have an impact on the pregnancy itself in terms of health complications, but also increases the chance of future diabetes and heart disease for both the mother and the baby – so it's critical that we understand why this increase is happening and how we can reverse the trend.

The researchers also observed a meaningful difference in certain racial/ethnic groups (with higher prevalence in Native, Asian, and Pacific Islander women), which is an important observation given that women in these groups are often very underrepresented in existing research – limiting our current ability to understand why these rates might be so much higher than other groups.

While the insights are discouraging, large scale data like this is so important to understand what is actually driving this increase and to inform further tailored and representative research. Additionally, this kind of data can help drive updates to clinical practices/guidelines to better support mothers and ultimately reduce the rates of gestational diabetes. 

Key excerpt:

“Northwestern scientists analyzed every U.S. birth for first singleton pregnancies from 2016 to 2024, using birth certificate data from the National Center for Health Statistics. The team then broke down the data by race and ethnicity and found that women who are American Indian or Alaska Native, Asian, Native Hawaiian or from other Pacific Islander groups had substantially higher gestational diabetes rates than other groups.…

“These data clearly show that we are not doing enough to support the health of the U.S. population, especially young women before and during pregnancy,” Shah said.”