Home> Articles > Twin Pregnancy Preterm Labor


Twin Pregnancy Preterm Labor

Preterm Delivery (before 37 w) is the most common complication of a twin pregnancy. The average twin pregnancy delivers at about 35 weeks   Women who have had a previous preterm single baby appear to be at higher risk for preterm delivery than other women with a twin pregnancy [1,2].  In addition,  twin pregnancies conceived by assisted reproductive technology (in vitro)  may also be at increased risk for preterm delivery compared to women with naturally conceived twins [3-5]. Lastly women who deliver  twins at less than 34 weeks' have an increased risk of  preterm birth in future pregnancies [6].

Signs and Symptoms of Preterm Labor

  • Regular or frequent contractions (tightening of the uterus), equal to or greater than 6 times in an hour. Sometimes this feels like tightening of the belly.

  • Menstrual – like cramps or abdominal cramps.

  • Low backache

  • Pelvic pressure

  • Increase or change in vaginal discharge (watery, mucus, or bloody)

  • Leakage of clear water or bleeding from the vagina

Call your doctor if you notice any of the above signs or symptoms. It is often  difficult to tell the difference between  true preterm labor and false labor . The diagnosis of preterm labor is usually made if there are regular contractions with effacement (thinning) of the cervix  to greater than or equal to  80%  and / or opening of the cervix to at least 2 centimeters.

What Causes Preterm Labor? 

Spontaneous (unprovoked) preterm labor may result from several causes including infection, inflammation,  vascular disease (poor blood supply to the uterus and placenta) , an overstretched uterus, and abnormalities  of the cervix . The cause of many preterm births is never found [18]

Prevention of Preterm Labor

Bedrest,  intramuscular  and long term use of oral medications to stop contractions (tocolytics) are not recommended for the prevention of preterm labor in multiple pregnancies because these treatments are either ineffective and/or may cause harm [7-11] Cervical cerclage (stitching the cervix closed) is also not recommended in multiple pregnancies except in specific circumstances  [7,12].

However, vaginal progesterone may be effective in reducing bad outcomes in women with a twin pregnancy and a cervical length of 25 mm or less [19].  Cervical pessaries, small ring-shaped devices which are inserted around the cervix, may also be effective in reducing bad outcomes in women with a twin pregnancy and a cervical length of less than 38mm [16].

If there is enough time the babies can be given a medication (corticosteroid) to help the lungs mature and reduce other complications of being born prematurely.  A shortened cervix is a strong predictor of preterm delivery in twin pregnancies . The graph below shows how the risk of preterm delivery begins to increase rapidly as the cervix shortens to less than 25 mm.

Some health care providers use the cervical length and the fetal fibronectin test to select twin pregnancies at high risk for preterm delivery  for treatment with  corticosteroids before the mothers have gone into preterm labor [14].

Reviewed by Mark Curran, M.D. FACOG


1. Recurrence risk of preterm birth in subsequent twin pregnancy after preterm singleton delivery.
Schaaf JM, Hof MH, Mol BW, Abu-Hanna A, Ravelli AC.
BJOG. 2012 Dec;119(13):1624-9. PMID: 23078576
2. Facco FL, Nash K, Grobman WA. Are women who have had a preterm singleton delivery at increased risk of preterm birth in a subsequent twin pregnancy?Am J Perinatol. 2008 Nov;25(10):657-9. doi: 10.1055/s-0028-1090592. Epub 2008 Oct 7.
PMID: 18841535
3. Moini A, et .al., Obstetric and neonatal outcomes of twin pregnancies conceived by assisted reproductive technology compared with twin pregnancies conceived spontaneously: a prospective follow-up study. Eur J Obstet Gynecol Reprod Biol. 2012 Nov;165(1):29-32.PMID: 22884795
4. Källén B,et al., Selected neonatal outcomes in dizygotic twins after IVF versus non-IVF pregnancies.
BJOG. 2010 May;117(6):676-82. doi: 10.1111/j.1471-0528.2010.02517.x. Epub 2010 Feb 24.
PMID: 20184569
5. Vasario E, IVF twins have similar obstetric and neonatal outcome as spontaneously conceived twins: a prospective follow-up study. Reprod Biomed Online. 2010 Sep;21(3):422-8.PMID: 20638334
6. Rafael TJ, et. al., Gestational age of previous twin preterm birth as a predictor for subsequent singleton preterm birth.Am J Obstet Gynecol. 2012 Feb;206(2):156.e1-6. PMID: 22098669
7.Prediction and prevention of preterm birth. Practice Bulletin No. 130. American College of Obstetricians and Gynecologists. Obstet Gynecol 2012;120:964–73. PMID:22996126
8. Klein K, et al., Vaginal micronized progesterone and risk of preterm delivery in high-risk twin pregnancies: secondary analysis of a placebo-controlled randomized trial and meta-analysis.
Ultrasound Obstet Gynecol. 2011 Sep;38(3):281-7. doi: 10.1002/uog.9092.
PMID: 21739499
9. Aboulghar MM, et al. The use of vaginal natural progesterone for prevention of preterm birth in IVF/ICSI pregnancies.Reprod Biomed Online. 2012 Aug;25(2):133-8. PMID: 2269531
10. Serra V,  et. al., Increased doses of vaginal progesterone for the prevention of preterm birth in twin pregnancies: a randomised controlled double-blind multicentre trial.BJOG. 2013 Jan;120(1):50-7. PMID: 22882759
11. Romero R,  et. al., Vaginal progesterone in women with an asymptomatic sonographic short cervix in the midtrimester decreases preterm delivery and neonatal morbidity: a systematic review and metaanalysis of individual patient data.Am J Obstet Gynecol. 2012 Feb;206(2):124.e1-19.  PMID: 22284156
12. Salomon LJ,et. al. Emergency cerclage in cases of twin-to-twin transfusion syndrome with a short cervix at the time of surgery and relationship to perinatal outcome. Prenat Diagn. 2008 Dec;28(13):1256-61. PMID: 19039797
13. Ehsanipoor RM, et. al., Gestational age at cervical length measurement and preterm birth in twins. Ultrasound Obstet Gynecol. 2012 Jul;40(1):81-6. doi: 10.1002/uog.10130. PMID: 22045546
14. Jaffe Lifshitz S,  Routine cervical length and fetal fibronectin screening in asymptomatic twin pregnancies: is there clinical benefit? J Matern Fetal Neonatal Med. 2013 Sep 5.  PMID: 23919826

16. Liem S, et al. Cervical pessaries for prevention of preterm birth in women with a multiple pregnancy (ProTWIN): a multicentre, open-label randomised controlled trial. Lancet. 2013 Oct 19;382(9901):1341-9. doi: 10.1016/S0140-6736(13)61408-7. Epub 2013 Aug 5.PMID: 23924878
17. Multiple gestation: complicated twin, triplet, and high-order multifetal pregnancy. ACOG Practice Bulletin No. 56. American College of Obstetricians and Gynecologists. Obstet Gynecol 2004;104:869–83.
Epidemiology and causes of preterm birth. Goldenberg RL, Culhane JF, Iams JD, Romero R. Lancet. 2008 Jan 5;371(9606):75-84.  PMID: 18177778

19. González-Quintero VH, et al., The association of gestational weight gain per institute of medicine guidelines and prepregnancy body mass index on outcomes of twin pregnancies.
Am J Perinatol. 2012 Jun;29(6):435-40. doi: 10.1055/s-0032-1304824. Epub 2012 Mar 7. PMID: 22399219

19. Effectiveness of progestogens to improve perinatal outcome in twin pregnancies: an individual participant data meta-analysis. Schuit E, et. al.,  Mol B; a Global Obstetrics Network (GONet) collaboration. BJOG. 2014 Aug 22. doi: 10.1111/1471-0528.13032. PMID: 25145491



Home | About | Disclaimer | Privacy | Contact

Copyright © 2013 -2014 by Focus Information Technology. All rights reserved.
This material may not be republished, broadcast, rewritten or redistributed.