Researchers studied 210 pregnancies in women who had weight loss surgery to understand their health needs and outcomes. They found that many women weren’t getting proper nutritional counseling before pregnancy, and many developed serious vitamin deficiencies during pregnancy. Babies born to these mothers were more likely to need special care in the hospital. The study shows that women who’ve had weight loss surgery need specialized medical care and nutrition support when planning to get pregnant and throughout their pregnancy to stay healthy and protect their babies.

The Quick Take

  • What they studied: How pregnancy goes for women who have had weight loss surgery, and what health problems they face during pregnancy
  • Who participated: 189 women who had weight loss surgery and were pregnant at least once between 2018 and 2022. Most were dealing with other health issues like diabetes, hormone problems, or depression
  • Key finding: More than 6 out of 10 pregnant women developed iron deficiency, and nearly half developed vitamin B12 deficiency. Less than half had talked to a nutrition expert before getting pregnant. Babies born to these mothers needed special hospital care more often than babies born to other mothers
  • What it means for you: If you’ve had weight loss surgery and are thinking about getting pregnant, you should see a nutrition specialist and your doctor regularly. You’ll likely need vitamin supplements during pregnancy, and your baby may need extra monitoring. This doesn’t mean you can’t have a healthy pregnancy—it just means you need specialized care

The Research Details

Researchers looked back at medical records from 189 women who had weight loss surgery and became pregnant between 2018 and 2022. They collected information about each woman’s health before surgery, during pregnancy, and after birth. They recorded details like weight, vitamin levels, any health problems during pregnancy, and how the babies were doing at birth.

This type of study is called a ‘retrospective audit,’ which means doctors reviewed past medical records instead of following women forward in time. While this method is quick and uses real-world data, it depends on how complete and accurate the medical records were.

Weight loss surgery changes how the body absorbs nutrients from food. This is important during pregnancy because a growing baby needs extra vitamins and minerals. By studying real pregnancies in women who had this surgery, doctors can understand what problems happen most often and how to prevent them. This helps create better care plans for future pregnancies

This study looked at a good number of pregnancies (210) from a specialized medical center that focuses on obesity care, which means the doctors had expertise in this area. However, not all women had complete information recorded—for example, only 167 women had iron levels checked. The study looked backward at records rather than following women forward, which can miss some details. The results may not apply to all hospitals or countries with different healthcare systems

What the Results Show

The study found that vitamin deficiencies were very common in pregnant women after weight loss surgery. Iron deficiency showed up in about 64% of women tested during the middle of pregnancy, and about 24% needed iron injections because pills weren’t enough. Vitamin B12 deficiency occurred in about 46% of women tested, with about 33% needing injections.

Another major finding was that most women weren’t getting proper nutrition counseling before pregnancy. Only 43% of women had seen a dietitian (nutrition specialist) before getting pregnant, even though this is very important for planning a healthy pregnancy.

Pregnancy and birth complications were common. About 44% of pregnancies had some kind of complication for the mother, and about 46% had complications for the baby. Most importantly, babies born to these mothers needed special care in the hospital much more often than babies born to other mothers—many needed to stay in special care nurseries or intensive care units.

The study also found that many women still had obesity (BMI over 30) before getting pregnant, even though they’d had weight loss surgery. This happened in about 56% of pregnancies. Many women had other health conditions like polycystic ovarian syndrome (a hormone problem), type 2 diabetes, depression, and anxiety. Some women got pregnant very soon after surgery—within 12 months—which may increase risks because the body is still adjusting to the surgery

Previous research has shown that weight loss surgery changes how the body absorbs nutrients, but this study provides more detailed information about exactly how common these problems are during pregnancy. The high rates of vitamin deficiencies match what smaller studies have suggested, but the detailed tracking of how many women needed injections and hospital care for babies adds important new information. The finding that most women weren’t getting pre-pregnancy counseling suggests there’s a gap between what doctors recommend and what actually happens in practice

Not all women had all tests done—some didn’t have iron or B12 levels checked, so the real numbers might be different. The study only looked at one hospital center, so results might be different in other places. Because researchers looked backward at records, they couldn’t control for other factors that might affect outcomes. The study didn’t compare these pregnancies to a group of pregnant women without prior surgery, so we can’t say for certain how much higher the risks really are. Some important information might have been missing from the medical records

The Bottom Line

If you’ve had weight loss surgery and want to get pregnant: (1) See a nutrition specialist before trying to conceive—this is strongly recommended based on this research; (2) Get your vitamin and mineral levels checked regularly, especially iron and B12; (3) Take vitamin supplements as recommended by your doctor; (4) Work with doctors who specialize in caring for pregnant women after weight loss surgery; (5) Plan your pregnancy at least 12-18 months after surgery if possible, to let your body adjust. Confidence level: High—these recommendations are based on clear evidence of what problems occur

This research is most important for women who have had weight loss surgery and are planning to get pregnant, or who are already pregnant. It’s also important for their partners, family members, and healthcare providers. Women who had weight loss surgery many years ago and are now thinking about pregnancy should especially pay attention. This doesn’t apply to women who haven’t had weight loss surgery or who don’t plan to get pregnant

You should start seeing a nutrition specialist at least 3-6 months before trying to get pregnant. Once pregnant, vitamin deficiencies can develop quickly—the study found iron problems by the middle of pregnancy. If you need vitamin injections, you’ll likely need them throughout pregnancy. Benefits of proper nutrition support include better health during pregnancy, fewer complications, and better outcomes for your baby. You may notice improved energy and fewer pregnancy symptoms within weeks of starting proper supplementation

Want to Apply This Research?

  • Track weekly vitamin and mineral supplement intake (iron, B12, folate, calcium, vitamin D) and record any symptoms like fatigue, shortness of breath, or tingling that might suggest deficiencies. Log the dates of any blood tests and results, especially iron and B12 levels
  • Set daily reminders to take prenatal vitamins and any prescribed supplements. Schedule and attend all nutrition specialist appointments before pregnancy and monthly during pregnancy. Log what you eat to help your dietitian identify any nutritional gaps. Track any pregnancy symptoms to discuss with your healthcare team
  • Create a monthly check-in routine: review supplement adherence, note any new symptoms, track appointment dates with your nutrition specialist and obstetrician, and record blood test results when available. Set alerts for when you need to refill prescriptions and schedule follow-up appointments. Share this information with all your healthcare providers to ensure coordinated care

This research describes what happened in one hospital’s experience with pregnant women after weight loss surgery. It is not medical advice. If you have had weight loss surgery and are pregnant or planning to become pregnant, you must consult with your own healthcare providers, including your obstetrician and a nutrition specialist, to develop a personalized care plan. Every pregnancy is unique, and your doctors need to know your complete medical history to give you appropriate recommendations. Do not start, stop, or change any medications or supplements without talking to your doctor first. This information is for educational purposes only and should not replace professional medical advice