Twins after IVF: what a twin pregnancy needs

A twin pregnancy places a greater load on the mother's body: blood volume, nutritional demands and pressure on the organs are all greater. This raises the risk of several complications that are known in advance: preterm birth, which is the most common, high blood pressure and pre-eclampsia, gestational diabetes, anaemia and slower growth of one of the babies. None of these is certain to happen, but all are actively watched for.

After IVF, twins most often come from the transfer of two embryos, but sometimes from the splitting of a single embryo. The first ultrasound therefore has an important task: to determine how many sacs and how many placentas there are. This detail, called chorionicity, is perhaps the most important piece of information in the whole twin pregnancy.

When each twin has its own placenta, the pregnancy is called dichorionic; this is the most common and safest type. When the twins share a single placenta, the pregnancy is called monochorionic, and it needs much closer follow-up, because shared blood vessels can create an imbalance between the two babies, known as twin-to-twin transfusion syndrome. This type is followed with ultrasound every two weeks from the second trimester.

Chorionicity is determined most accurately early, before week 14, and this is why the first detailed ultrasound is so important. Knowing the placenta type from the start means knowing exactly how often and what to check for the rest of the pregnancy.

A twin pregnancy is followed with regular ultrasounds to check the growth of each baby and the amount of amniotic fluid, usually every 4 weeks in dichorionic and every 2 weeks in monochorionic twins. Blood pressure and urine are checked at every visit for signs of pre-eclampsia, and the test for gestational diabetes is done. Haemoglobin is followed for anaemia, and iron and folic acid supplementation is often recommended.

The mother may feel more tiredness, nausea and bloating than in a usual pregnancy, and this is expected. What needs attention are the signs of preterm labour: regular contractions, persistent lower back pain, pelvic pressure, a change in discharge or leaking fluid. These are reported without waiting, because in twins preterm birth is the main risk.

In twins, birth is usually planned before full term, because the risk to the babies rises if the pregnancy goes on too long. For uncomplicated dichorionic twins, birth is usually planned around week 37; for monochorionic twins a little earlier, around week 36. These are general guidelines that the team adapts to the course.

The mode of birth, vaginal or caesarean, depends on the position of the first twin, the placenta type, the course of the pregnancy and the mother's preference after a full conversation. Both can be safe in the right conditions. The plan is discussed early, not on the day of birth, so the mother knows what to expect and there are no surprises.