What Expecting Parents Need To Know About Preterm Labor

Preterm labor occurs when the body begins the process of labor before 37 weeks of pregnancy. Sometimes preterm labor can be stopped, and other times it progresses to birth.  

In this article, you’ll learn about potential risk factors and symptoms of preterm labor as well as ways in which preterm labor may be managed by your team. You’ll also learn some ways you can support a healthy, full-term pregnancy. 

How Do I Know If I’m at Risk of Preterm Labor? 

While preterm labor can happen without warning, some factors may increase your risk (1): 

• Previous preterm birth 
• Carrying twins or more 
• Short cervix or history of cervical procedures 
• Uterine abnormalities 
• Vaginal infections (e.g., BV, UTIs, STIs) 
• Chronic stress or inflammation 
• Certain autoimmune conditions 
• Low progesterone levels 
• Nutrient deficiencies 

If you have one or more of these risk factors, your provider may recommend additional monitoring, which may include more frequent prenatal visits, cervical length checks by ultrasound, progesterone supplementation, or other supportive interventions aimed at reducing your risk of preterm labor. More on this below. 

Sometimes pregnant mothers with certain risk factors may be prescribed baby aspirin. If you’d like to learn more about this, read this article: Low-Dose Aspirin in Pregnancy: Potential Benefits & Risks 

Preterm Labor Signs to Watch for

Not all early labor feels intense or dramatic. Some signs can be subtle… And sometimes it can be hard to tell the difference between regular pregnancy symptoms, like Braxton hicks, and actual preterm labor. Watch for the following symptoms (2,3): 

• Regular tightening or contractions (even if painless) 
• Pelvic pressure or a sensation of baby “bearing down” 
• Low backache or cramping similar to a period 
• Change in vaginal discharge, especially if it becomes very watery or bloody 
• General sense that something doesn’t feel right 

If you notice symptoms of preterm labor, call your provider.  

To learn more, read this article: Braxton Hicks vs. Labor Contractions: How to Tell the Difference 

What Might Your Provider Recommend if Preterm Labor is a Concern? 

If you’re showing early signs of labor or identified as high-risk, your provider may offer one or more of the following interventions (2): 

Referral to a Specialist 

If your primary provider is a midwife and you are showing signs of preterm labor they may refer you to an OB/GYN or a maternal-fetal medicine specialist (MFM). These providers can often co-manage your care, offering advanced testing, treatment, and hospital-based support if needed. In many cases, your midwife may continue to provide support, too. 

To learn more about the providers who may be on your team, read this article: Assembling Your Birth Team: Who’s Who & How to Choose The Right Support For Your Pregnancy 

Cervical Length Monitoring 

Cervical length monitoring is typically done through a transvaginal ultrasound, which allows your provider to measure the length of your cervix. This can help assess your risk of preterm labor, particularly if you have known risk factors like a history of preterm birth or cervical surgery. 

A shorter-than-expected cervix (usually under 25 mm before 24 weeks) may indicate that your body is preparing for labor too early (3). In some cases, this information can help guide preventative care, such as starting vaginal progesterone or considering a cerclage (a stitch to help keep the cervix closed). 

Progesterone Therapy 

If your cervix is measuring short or you’ve had a previous preterm birth, your provider may recommend progesterone supplementation to help support the pregnancy. Progesterone is a hormone that helps maintain the uterine lining and reduce inflammation, both important in preventing early labor (4). 

There are two main forms used during pregnancy: 

• Vaginal progesterone (typically a gel or suppository) is commonly used if you have a short cervix. 
• Injectable progesterone (17-OHPC) may be offered if you have a history of spontaneous preterm birth. 

Cerclage 

Cerclage is a surgical procedure where a stitch is placed around the cervix to help keep it closed during pregnancy. It’s typically offered to people diagnosed with cervical insufficiency, before 24 weeks (5). 

The procedure is done vaginally and usually takes under an hour. Most people go home the same day, and recovery tends to be fairly quick. You may be advised to avoid heavy lifting or sexual activity afterward, depending on your provider’s guidance. 

Not everyone with a short cervix needs a cerclage. This option is generally reserved for those with a very specific history or cervical measurement pattern. 

Medications to Delay Labor or Support Your Baby’s Health 

If labor begins early, your provider may use one or more of the following medications. These are often used in hospital settings and chosen based on your gestational age and symptoms: 

• Tocolytics: Medications that can temporarily stop or slow contractions (6). These don’t necessarily prevent preterm birth long term but may buy time for other interventions to work. 
• Corticosteroids: If you’re between 24–34 weeks and at risk of delivery, a short course of steroids (like betamethasone) may be given to speed up fetal lung development, reducing the risk of breathing problems after birth (7). 
• Magnesium sulfate: Typically offered if delivery seems likely before 32 weeks. It may help protect your baby’s brain (8). 

As with any medical intervention, there are pros and cons to consider. There certainly is a time and place for interventions like these, and it is important to understand that medications can be critical in certain situations. It’s always okay to ask your provider about the reasons for their recommendation, potential side effects, and whether any alternatives exist.  

Understanding Bed Rest, Pelvic Rest, and Modified Activity 

Depending on your risk level, your care team may recommend changes to your daily routine (9): 

Full Bed Rest 

Rarely recommended today due to risks like blood clots and muscle loss. Still may be used in highly specific cases under medical supervision. 

Modified Bed Rest 

More common than full bed rest. This may include: 

• Limiting standing and walking 
• Avoiding lifting heavy objects (typically more than 10–20 lbs) 
• Reducing physical exertion and stress 
• Working from home or adjusting responsibilities 

Pelvic Rest 

This means avoiding anything that could stimulate the cervix, including: 

• Sexual intercourse 
• Vaginal exam (unless medically necessary) 
• Orgasm 

These recommendations are customized based on your history, current symptoms, and gestational age. 

What You Can Do: Evidence-Based Strategies for Supporting a Full-Term Pregnancy 

If you’ve experienced early signs of labor, seen your provider, and been reassured that it’s safe to go home, it can feel unsettling to simply wait and hope for the best. That “wait and see” period often comes with questions: Is there anything else I can do? 

While it’s true that not everything is within our control, there are some ways you can care for your body and support a healthy pregnancy from home…  Just know that these strategies do not replace medical treatment or professional guidance.  

Ensure Adequate Omega-3 Intake 

• What the science says: Sufficient DHA (a type of omega-3) intake is associated with a lower risk of early preterm birth (10).
• Sources: Fatty fish, fish oil, DHA supplements
• Note: Supplementation is especially important if your diet is low in seafood. 

To learn more, read this article: The Importance of Omega-3 Fatty Acids During Pregnancy 

Get Enough Vitamin D 

• What the science says: Low vitamin D levels (especially during early pregnancy) have been linked to increased preterm birth risk (11).
• Sources: Sun exposure, fatty fish, D3 supplements
• Tip: Ask your provider to test your 25(OH)D levels and supplement if needed. 

To learn more about Vitamin D supplementation, read this article: Better Together: Vitamins D3 & K2 

Maintain Healthy Iron Levels 

• What the science says: Severe anemia is associated with higher risk of preterm birth (12). Ensuring adequate iron, especially in the second and third trimesters, is important for a healthy pregnancy..
• Sources: Red meat, lentils, spinach, beef liver, iron supplements.

To learn more about supplementing with iron, read this article: A Guide To Iron Supplementation 

Supplement with Folate 

• What the science says: Folate deficiency is linked to adverse outcomes, including preterm birth (13).
• Sources: Leafy greens, beef liver, legumes, prenatal vitamins.
• Note: Folate is different from synthetic folic acid and is more easily processed by people with MTHFR gene variants (14). 

Manage Stress 

• What the science says: High levels of maternal stress during pregnancy are associated with an increased risk of preterm birth (15). Not all stress leads to early labor, but stress-related hormonal changes (such as elevated cortisol and placental CRH) are believed to play a biological role in triggering labor too soon in some pregnancies (15), and The American College of Obstetricians and Gynecologists now recommends routine psychosocial screening during pregnancy (16). 

What might help: 

• Deep breathing or mindfulness-based stress reduction 
• Gentle prenatal yoga (if approved by your provider) 
• Acupuncture or craniosacral therapy 
• Emotional support from counseling, peer groups, or therapy 

Summary 

Preterm labor can happen unexpectedly, but certain risk factors, such as previous preterm birth, infections, low progesterone, or chronic stress, may increase your chances. Knowing the signs of preterm labor and getting timely medical support help ensure a positive outcome. Your provider may offer tools like progesterone therapy, cervical monitoring, or medications to delay labor if needed. In addition to medical care, research supports several proactive steps you can take at home to support a full-term pregnancy. Ensuring adequate intake of omega-3s (DHA), vitamin D, iron, and folate, as well as stress management can all help support a healthy pregnancy.  

References: 

1. National Institutes of Health. (2023). What are the risk factors for preterm labor and birth? Www.nichd.nih.gov. https://www.nichd.nih.gov/health/topics/preterm/conditioninfo/who_risk 
2. Jenkins SM, Mikes BA. Preterm Labor. [Updated 2025 Feb 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK536939/ 
3. O’Hara S, Zelesco M, Sun Z. Cervical length for predicting preterm birth and a comparison of ultrasonic measurement techniques. Australas J Ultrasound Med. 2013 Aug;16(3):124-134. doi: 10.1002/j.2205-0140.2013.tb00100.x. Epub 2015 Dec 31. Erratum in: Australas J Ultrasound Med. 2013 Nov;16(4):210-211. doi: 10.1002/j.2205-0140.2013.tb00251.x. PMID: 28191186; PMCID: PMC5029998. 
4. Choi SJ. Use of progesterone supplement therapy for prevention of preterm birth: review of literatures. Obstet Gynecol Sci. 2017 Sep;60(5):405-420. doi: 10.5468/ogs.2017.60.5.405. Epub 2017 Sep 18. PMID: 28989916; PMCID: PMC5621069. 
5. Alfirevic Z, Stampalija T, Medley N. Cervical stitch (cerclage) for preventing preterm birth in singleton pregnancy. Cochrane Database Syst Rev. 2017 Jun 6;6(6):CD008991. doi: 10.1002/14651858.CD008991.pub3. PMID: 28586127; PMCID: PMC6481522. 
6. Web Annex. Evidence-to-decision frameworks. In: WHO recommendation on tocolytic therapy for improving preterm birth outcomes. Geneva: World Health Organization; 2022. Licence: CC BY-NC-SA 3.0 IGO.  https://iris.who.int/bitstream/handle/10665/363130/9789240057241-eng.pdf 
7. American College of Obstetricians and Gynecologists. (2017). Antenatal Corticosteroid Therapy for Fetal Maturation. Www.acog.org. https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2017/08/antenatal-corticosteroid-therapy-for-fetal-maturation 
8. Shepherd ES, Goldsmith S, Doyle LW, Middleton P, Marret S, Rouse DJ, Pryde P, Wolf HT, Crowther CA. Magnesium sulphate for women at risk of preterm birth for neuroprotection of the fetus. Cochrane Database Syst Rev. 2024 May 10;5(5):CD004661. doi: 10.1002/14651858.CD004661.pub4. PMID: 38726883; PMCID: PMC11082932. 
9. American College of Obstetricians and Gynecologists. (2023). Preterm Labor and Birth. Www.acog.org. https://www.acog.org/womens-health/faqs/preterm-labor-and-birth 
10. Best KP, Gibson RA, Makrides M. ISSFAL statement number 7 – Omega-3 fatty acids during pregnancy to reduce preterm birth. Prostaglandins Leukot Essent Fatty Acids. 2022 Nov;186:102495. doi: 10.1016/j.plefa.2022.102495. Epub 2022 Sep 30. PMID: 36228573. 
11. Qin LL, Lu FG, Yang SH, Xu HL, Luo BA. Does Maternal Vitamin D Deficiency Increase the Risk of Preterm Birth: A Meta-Analysis of Observational Studies. Nutrients. 2016 May 20;8(5):301. doi: 10.3390/nu8050301. PMID: 27213444; PMCID: PMC4882713. 
12. Khezri R, Salarilak S, Jahanian S. The association between maternal anemia during pregnancy and preterm birth. Clin Nutr ESPEN. 2023 Aug;56:13-17. doi: 10.1016/j.clnesp.2023.05.003. Epub 2023 May 6. PMID: 37344062. 
13. Lazar VMA, Rahman S, Chowdhury NH, Hasan T, Akter S, Islam MS, Ahmed S, Baqui AH, Khanam R. Folate deficiency in pregnancy and the risk of preterm birth: A nested case-control study. J Glob Health. 2024 Jul 12;14:04120. doi: 10.7189/jogh.14.04120. PMID: 38991209; PMCID: PMC11239188. 
14. Carboni L. Active Folate Versus Folic Acid: The Role of 5-MTHF (Methylfolate) in Human Health. Integr Med (Encinitas). 2022 Jul;21(3):36-41. PMID: 35999905; PMCID: PMC9380836. 
15. Wadhwa PD, Entringer S, Buss C, Lu MC. The contribution of maternal stress to preterm birth: issues and considerations. Clin Perinatol. 2011 Sep;38(3):351-84. doi: 10.1016/j.clp.2011.06.007. PMID: 21890014; PMCID: PMC3179976. 
16. American College of Obstetricians and Gynecologists. (2025). Patient Screening. Www.acog.org. https://www.acog.org/programs/perinatal-mental-health/patient-screening