Scientists from the Queen Mary University of London (QMUL) have analyzed over 30,000 women to identify the ideal delivery time for twin pregnancies to reduce the risk rates of stillbirth. Jointly collaborated by the Global Obstetric Network (GONET), the findings are likely to reduce the increasing rates of stillbirths.
Upon concluding the most extensive review of its kind, the experts recommended that dichorionic twins (twins with separate placenta or fraternal twins) should be offered delivery at 37th week of pregnancy. On the other hand, for women expecting monochorionic twins (twin who share a placenta) should not be offered delivery before 36th week of their pregnancy.
During this investigation, the researchers had no direct interactions with the parents who have had twin children pregnancies, but they used the information from the Medline, Embase and Cochrane databases till December 2015. After the close analysis of several meta-analyses and cohorts, the crucial findings of the study were published in the British Medical Journal (BMJ) on 6th September, 2016.
After analyzing a total of 29,685 dichorionic and 5,486 monochrionic pregnancies, the results were gathered which can also be added by National Institute for Health and Care Excellence (NICE) in their multiple pregnancy management guidelines in future.
Currently, NICE statistics say that 60% of the twin pregnancy deliveries result before 37 weeks of pregnancy. The institute has suggested that in uncomplicated monochorionic twin pregnancies, birth in the 36th week has no link with health complications. On the other hand, for dichorionic twin pregnancies, delivery in the 37th week has no association with adverse health effects.
However, for both twin pregnancies types, extending the delivery to 38th week has serious effects on health. On the contrary, in singleton pregnancies, the delivery time can range between 37 and 40 weeks.
Researchers of this study estimated that the twin pregnancy complications in the UK have been on an exponential rise since year 2015. These complications included unexpected stillbirth and neonatal death which peaked during year 2013 and 2014, increasing by 419% altogether, inflicting a cost of over £90 million.
When a woman is pregnant with two or more fetuses, her body endurance is tested and often vulnerabilities lead to birth and neonatal complications. On an average, twin pregnancies have 13 fold higher rate of stillbirth in monochroionic twins and five folds higher in dichorionic twins when compared with singleton pregnancies.
The researchers of the study found that the management and risk of neonatal death from delivery at 37 weeks’ gestation were balanced. While a delay in delivery by a week, extending to 38 weeks, leads to additional 8.8 prenatal deaths per 1,000 pregnancies. Monochorionic pregnancies beyond 34 weeks, as compared to neonatal deaths after 36 weeks, lead to additional 2.5 deaths per 1,000 pregnancies which was statistically insignificant.
The researchers also said that the risk of twin pregnancy complications is increased by late deliveries, but premature births also account for neonatal deaths. Thereby, to have an optimal delivery time is of integral importance to the health of baby and mother alike.
In twin pregnancies, there is always a risk for a chromosomal abnormality during cell division, which may lead to structural anomalies such as heart defects. It is also very common for the one twin to grow slowly, while the other shows a healthy growth. Often this does not lead to a health hazard but a certain risk is always present.
This difference in fetal development is known as intrauterine growth restriction (IUGR) which can lead to health problems in some cases. However, the likelihood of this complication is more common in monochorionic twins which is why early birth by caesarean section is often recommended.
Another twin pregnancy complication which is rather rare is called twin-to-twin transfusion syndrome (TTTS) which takes place in monochorionic twins when blood connections in the placenta are shared by both developing fetuses, consequently leading to one fetus getting more blood supply and the other getting lesser volume of blood.
Similarly, the risk of getting tangled umbilical cords and choking is also prevalent in monochorionic twins.
About 30% of the women who are pregnant with twins experience vaginal bleeding as compared to 20% of the women expecting single child who experience this complication. While at times vaginal bleeding is harmless, at other times it can be a sign of miscarriage, inherited disorder in the fetus, benign growth on the cervix, vaginal or cervical infection or hormonal imbalance.
There is a high risk in a twin pregnancy to have a miscarriage of one baby while the other child survives if no further complications are encountered. Known as vanishing twin syndrome, the underlying reason for the loss is often referred to as chromosomal abnormalities or improper cord implantation. If this complication is met with during the first trimester, the surviving twin usually remain healthy.
However, if it happens in the second or third trimester, the risk of harm to the surviving fetus increases.
Besides that, the risk of gestational diabetes and pre-eclampsia in the expecting women is always present which can increase in twin pregnancies. Therefore, regular appointments with gynecologist, health monitoring, ultrasounds, blood tests and other prenatal testing are of utmost importance to minimize the risks of complications.
This study has important clinical implications for managing twin pregnancies globally and minimizing stillbirths and neonatal death. This view was aptly reflected by study’s co-author, Professor Thangarantinam, who said, “There is a global drive to prevent stillbirths and we know that twin pregnancies are a major risk factor for stillbirths in high income countries.
We hope that this research will help to complement national and international efforts to reduce the rates of stillbirth and unexpected neonatal complications in babies from women with twin pregnancies and will be useful to national guideline and hospital policymakers.”