5 Birth Defect Risk Factors Patients Should Know

Doctor holding pregnant woman hand with catheter, birth defects prevention
What are some notable risk factors for birth defects that health care professionals should discuss with prospective parents to better prevent them?

As a health care professional, one of the most important parts of working with pregnant patients is helping them to identify the development of birth defects. This can be a challenging endeavor, as not all birth defects have clear and identifiable risk factors.

Prospective parents are likely aware of certain factors that increase the odds of birth defects, such as smoking cigarettes and consuming alcohol. However, it is still important to discuss with them a variety of factors that may have an impact on birth defect development both before and during pregnancy. Doing so can provide them with a necessary understanding of what risk factors they may already have, and which ones they can actively work to mitigate. Here are 5 risk factors for birth defects that your patients should know about.

1. Age

One commonly discussed risk factor for birth defects is age; research has suggested that the odds of chromosomal abnormalities are higher in older mothers (>35 years).¹ Though this does not suggest that birth defects are a guarantee for older mothers, it is something that should be discussed with their health care provider to work on better mitigating additional risk factors.

It has also been suggested that teenage pregnancies may carry an increased risk of birth defects. A 2022 study in Frontiers in Public Health examined data from 51,571 cases of birth defects among nearly 2 million births in China from 2012 to 2018 and found that teen pregnancies had more risk of neural tube defects, gastroschisis, and multiple birth defects than pregnancies in those aged 25 to 29.² The researchers concluded that more was needed to provide teens at risk of pregnancy with reproductive education and prenatal health care.

2. Diabetes

A patient’s existing medical conditions may increase the risk of birth defects, notably diabetes. The less controlled a patient’s diabetes, the higher the risk; having high blood sugar at the time of conception increases the risk of birth defects and preterm birth, while high blood sugar during pregnancy correlates with an increased risk of being born too large.³

Researchers in a 2022 study published in PLoS Medicine combed through the data of over 80 million births and found a strong correlation between maternal diabetes and congenital abnormalities.⁴ In particular, they found abnormalities and congenital heart disease to be a greater risk in those with pre-gestational diabetes mellitus than in those with gestational diabetes mellitus, though both were at a heightened risk. This suggests a need for health care professionals to have discussions with prospective parents with diabetes before conception to help keep their condition in check before gestation.

3. Exposure to Pollutants

The environment in which prospective parents live may play a larger role in birth defect risk than they may realize, particularly if they receive greater exposure to pollutants. A study published in PLoS One in 2022 examined pregnant individuals’ proximity to mountaintop removal mining in Appalachian Kentucky from 1997 to 2003 and found a correlation between gastrointestinal birth defects and residential proximity to mining.⁵ Prospective parents should be aware of pollutants and, if possible, consider the area they reside when trying to conceive.

4. Nutritional Deficiency

It is vital for expectant mothers to receive sufficient nutrients for both themselves and their babies. The most important thing to ingest is folic acid. A daily intake of 400 mg of folic acid has been shown to help prevent neural tube defects.⁶ Despite the importance of folic acid, it is estimated that only 2 out of 5 women considered to be of childbearing age have a daily intake of folic acid. This is a factor in particular that should be stressed to prospective parents, as some clinicians recommend starting intake 1 month before pregnancy.¹

5. Use of Certain Medications

One of the most important things health care professionals should discuss with expecting or prospective parents is medication use, both prescription and over-the-counter. Though many mothers will need to continue with medication depending on the condition they take it for, some medicines can increase the risk of birth defects. There are also many medications where there is not sufficient information on how they affect pregnant women. These medications should be talked about at length so that patients know the potential risks, whether larger dosages can increase the risks, and whether there are alternative treatments they can look into.

This article originally appeared on Clinical Advisor


1. What are birth defects? US Centers for Disease Control and Prevention. https://www.cdc.gov/ncbddd/birthdefects/facts.html. Updated November 5, 2021. Accessed January 27, 2023.

2. Chen X, Lou H, Chen L, Muhuza MPU, Chen D, Zhang X. Epidemiology of birth defects in teenage pregnancies: Based on provincial surveillance system in eastern China. Front Public Health. 2022 Dec 6;10:1008028. doi: 10.3389/fpubh.2022.1008028. PMID: 36561870; PMCID: PMC9763884.

3. Diabetes during pregnancy | Maternal infant health. US Centers for Disease Control and Prevention. https://www.cdc.gov/reproductivehealth/maternalinfanthealth/diabetes-during-pregnancy.htm. Updated June 12, 2018. Accessed January 27, 2023.

4. Zhang TN, Huang XM, Zhao XY, Wang W, Wen R, Gao SY. Risks of specific congenital anomalies in offspring of women with diabetes: A systematic review and meta-analysis of population-based studies including over 80 million births. PLoS Med. 2022 Feb 1;19(2):e1003900. doi: 10.1371/journal.pmed.1003900. PMID: 35104296; PMCID: PMC8806075.

5. Cooper DB, Walker CJ, Christian WJ. Maternal proximity to mountain-top removal mining and birth defects in Appalachian Kentucky, 1997-2003. PLoS One. 2022 Aug 11;17(8):e0272998. doi: 10.1371/journal.pone.0272998. PMID: 35951600; PMCID: PMC9371306.

6. How many people are affected by/at risk for birth defects? National Institute of Child Health and Human Development. https://www.nichd.nih.gov/health/topics/birthdefects/conditioninfo/risk#. Updated May 4, 2022. Accessed January 30, 2023.