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The complications of twin pregnancy

twin pregnancy

Did you get your antenatal ultrasound & discovered you are expecting twins? Though it is certainly a period of joy for you and your partner, it’s important to be aware of the risks that come with multiple pregnancies and understand how to manage them.

Types of twin pregnancy

  1. Identical or monozygotic twins are those in which a single sperm fertilizes a single egg. This fertilized egg divides into two and goes on to form twins. These babies have the same gender, features, and habits.
  2. If two eggs are fertilized by two sperm, the resulting twins would be fraternal or dizygotic twins. They can have the same or different gender, and there are hardly any similarities between them.

How common is it?

Having twins is not very common. Statistically, the occurrence of twins is 1 in every 250 pregnancies.

Who is more prone to have twins?

Significant causes of twin pregnancies are:

  • In vitro fertilization (IVF)
  • Ovulation induction
  • Advancing maternal age

Some studies have suggested that women with a body mass index (BMI) of 30 kg/m2 or above are more likely to conceive twins.

What are the complications associated with twin pregnancy?

  1. Preterm delivery

There is a considerable risk of premature delivery. Statistically, 50% of twin pregnancies deliver before 37 weeks, and 10% deliver even before 32 weeks of gestation. The reason for this is multifactorial, but the excessive enlargement of the uterus remains the point of focus.

  1. Preeclampsia

A mother with twin gestation has a risk of developing hypertension and preeclampsia. An evaluation of blood pressure and proteinuria is mandatory.

  1. Gestational diabetes

In Gestational diabetes mellitus (GDM), there are high sugar levels in the blood. It usually happens after 20 weeks of gestation and goes away on its own after delivery of the baby. Your healthcare provider will get your OGTT test to rule out this complication.

  1. Twin-twin transfusion syndrome

It is a rare but severe complication of monozygotic (identical) twins. Since there are intra-placental vascular connections between the two, it can lead to abnormal circulation, and one twin starts pumping blood to the other. This can become dangerous for the life of both babies. In this condition, it is recommended to have imaging scans every two weeks starting at 16 weeks. The imaging study provides an opportunity for surveillance of twin-twin transfusion syndrome.

  1. Suboptimal weight gain

The Institute of Medicine suggests weight gain for women carrying twins by 25 to 54 pounds (11 to 25 kg). Suboptimal maternal weight gain is associated with an increased risk for fetal growth restriction.

  1. Iron-deficiency anemia

Iron deficiency anemia is highly prevalent in women with twin gestations. The research was conducted from 2011 to 2014 on 83 women carrying multiple fetuses (twins, triplets, or quadruplets). 44.6% of women were found to have iron deficiency anemia at the time of delivery. There are known associations between iron deficiency and adverse maternal and neonatal outcomes. Additional screening and iron supplementation may be necessary during pregnancy.

  1. Placenta previa

All twin gestations are at an increased risk for abnormal placentation (placenta previa) and rarely Vasa Previa (when fetal blood vessels run near the internal opening of the uterus). Transvaginal scan at 18 weeks with color Doppler can confirm the presence of vasa previa.

  1. Congenital anomalies

Twins have an additional risk for congenital anomalies—specifically, the midline and cardiac abnormalities occurring in monozygotic (identical) twins.

An insight from mamahood

As you now know, there are risks associated with twin or multiple pregnancies. However, in most cases, you can reduce and eliminate these risks with routine obstetric care. It includes a review every four weeks until 24 weeks gestation, then every two weeks until 32 weeks gestation, and then weekly evaluation till delivery. The intrapartum management of twins should begin in the antenatal period.

Although vaginal delivery is not an absolute contraindication in twin pregnancies, the rate of planned cesarean sections remains high. Every mama-to-be who’s carrying twins should be aware of the possible risks associated with it. Only through awareness can you seek medical help on time.

Our References

Mamahood content is written by practicing physicians and healthcare professionals who rely on evidence-based resources, the latest research, and their experience to ensure our users get credible and updated information they can trust.

  • Ru Y., Pressman E.K., Cooper E.M., Guillet R., Katzman P.J., Kent T.R., Bacak S.J., O’Brien K.O. Iron deficiency and anemia are prevalent in women with multiple gestations. Am. J. Clin. Nutr. 2016;104:1052–1060. DOI: 10.3945/ajcn.115.126284. [PubMed] [CrossRef] [Google Scholar]
  • Wierzejska RE. Review of Dietary Recommendations for Twin Pregnancy: Does Nutrition Science Keep Up with the Growing Incidence of Multiple Gestations? Nutrients. 2022 Mar 8;14(6):1143. DOI: 10.3390/nu14061143. PMID: 35334799; PMCID: PMC8953105.
  • Ross V., Reidy K., Doyle L.W., Palma-Dias R., Umstad M.P. Outcome of twin pregnancies complicated by a neural tube defect. Twin Res. Hum. Genet. 2018;21:263–268. DOI: 10.1017/thg.2018.25. [PubMed] [CrossRef] [Google Scholar]
  • Murray SR, Stock SJ, Cowan S, Cooper ES, Norman JE. Spontaneous preterm birth prevention in multiple pregnancy. Obstet Gynecol. 2018 Jan;20(1):57-63. DOI: 10.1111/tog.12460. Epub 2018 Jan 28. PMID: 30008614; PMCID: PMC6034359

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