Doctor's Corner - Important health facts for the second trimester
The second trimester brings with it an end to the nausea and vomiting, and the start of those miraculous fetal movements paired with the look and feel of pregnancy. It is also the time to assess the results of the Down’s syndrome test.
The amniocentesis is a test where a needle is passed though the abdominal wall into the gestational sac to collect amniotic fluid for testing either confirming or not the presence of Down syndrome. This is performed between 16 and 22 weeks of your pregnancy. Unfortunately like any test, an amniocentesis does not come without complications, and there is a 1% risk of miscarriage.
For those couples who have missed the test, it would be wise to do a similar screening test early in the second trimester. This screening test is slightly less reliable, but will still provide a risk assessment from which further confirmatory tests can be performed. The screening test includes only the mother’s age and a blood test. Women over the age of 35 years carry a significantly higher risk and might necessitate a further confirmatory test to put the couple at ease.
One can expect fetal movements to start between 18 to 20 weeks, if it is your first pregnancy. However, for the mothers who have been pregnant before, it is quite normal for fetal movements to start slightly earlier, between 16 to 18 weeks. At first, it may feel like a sensation of butterflies in the tummy. This feeling will then grow in intensity as the baby grows. Fetal movements are an exciting indicator of fetal health and wellbeing. If, at this stage, you are not experiencing any fetal movement, it would be advisable to seek medical advice.
The most important event during the second trimester is the anomaly scan, where the fetus is now big enough to be assessed for all structural development and potential abnormalities. This ultrasound is usually performed at around 22 weeks and it is done to assess the fetus from top to bottom. The brain and spine can be seen, so even subtle abnormalities like spina bifida or Dandy Walker anomalies may be detected. The thorax and abdominal cavities can also be seen and the heart, stomach, kidneys, bladder and important blood vessels are assessed. Looking at the limbs, “soft markers” like club feet can be noted and congenital abnormalities or syndromes excluded.
In the second trimester, it is a good time to confirm, with some degree of certainty, the gender of the baby for parents who want to know the sex. This is established through an ultrasound scan. Along with the gender, more serious problems can also be noted. This could include abnormal placental (after birth) positions, cervical length, early growth and amount of amniotic fluid abnormalities. This ultrasound is very important as it sets a baseline for later scans, as it provides an accurate gestational age, especially when decisions for delivery need to be made later. If growth restriction occurs, it will be easy to confirm if all parameters were noted as normal at this stage.
Leading causes of maternal deaths and neonatal morbidity in South Africa often occur after 20 weeks, therefore, assessing both fetus and mother at this stage can prevent serious complications. Prevention is always better than cure. These conditions include: complications from HIV infection, internal bleeding, and pregnancy induced blood pressure and blood pressure irregularities as a result of pre-pregnancy medical problems such as heart disease, etc. Fortunately, most of these conditions can be controlled and prevented by early detection and treatment.
It is important for expecting mothers to know that even if it is the first pregnancy, they will know if their baby is not doing well. It is important to follow your instincts, so if there is any suspicion that something might be out of sorts, seek help immediately. Your body will undergo many changes over the next few months, so be sure to stay informed and comfortable now to avoid any confusion later.