Obstetric monitoring in high-risk pregnancies

For all women, pregnancy is an exciting and rewarding time in their lives, but it requires a proper follow-up to achieve a satisfactory outcome for both the pregnant woman and her baby.

Pregnancies considered “high-risk” require special care and closer monitoring.  Fortunately, these cases only affect 10% of all pregnancies and nowadays, technology and medical science have developed effective methods to prevent or control complications in a positive way. It is therefore essential to earlyidentify those pregnant women with risk factors through a good medical history and to assess their relative importance in order to reduce the negative consequences and achieve the best outcome at the end of the pregnancy. We should not panic if our pregnancy is “labelled” as high risk, as in most cases it only implies a greater number of visits, and not possible problems during pregnancy.

Cases of obstetric risks

There are many situations that can categorise a pregnancy as high-risk. Among them:

1. Maternal pathologies prior to pregnancy, including any chronic disease: diabetes, hypertension, heart disease, coagulopathies, obesity and underweight, epilepsy or uterine malformations, among others.
2. A second group is made up of pregnant women with an unfavourable obstetric history, that is, situations in previous pregnancies that may increase the risk of a complication in the current pregnancy, such as: reduced foetal growth, gestational-induced hypertension, foetal malformations, premature births, intrauterine foetal death or repeated miscarriages.
3. Finally, a third group consists of foetal-placental causes occurring during the course of the current pregnancy, such as: multiple pregnancy, foetal malformations, lower foetal weight than expected by ultrasound, threat of premature delivery, placental insufficiency or gestational diabetes.

Greater control and follow-up

In these pregnancies, stricter and more specialised monitoring is necessary, always assisted by a multidisciplinary team. This team includes highly qualified obstetricians with proven experience in the management of maternal and foetal disease together with support professionals: molecular biologists, geneticists, endocrinologists, midwives, paediatricians and anaesthetists. They must also have the necessary technical resources: high-end ultrasound scanners and their own laboratory to obtain and process all current prenatal diagnostic techniques.

The aim is to offer the pregnant woman individualised attention, as this usually involves a certain level of concern and worry. The number of extra visits will depend on the situation that led to the pregnancy being considered high-risk and aims to reduce, as far as possible, the risks to the baby and to arrive at the birth in the best possible conditions.

Obstetric screening from the age of 40 onwards

We are finding an increasing number of patients who wish to become pregnant after the age of 40, so it is not uncommon to find pregnant women in their 50’s. Is there any special pregnancy monitoring to be done in these patients? The answer is yes.

Before going into the differences in monitoring, we will dedicate a few lines to the preconception visit, since this is not only where we will receive advice on the risks, but also where a study of our general health will be carried out in order to detect possible alterations and be able to correct them beforehand, thus reducing the risk of complications.

First trimester monitoring

Increasing age in women leads them to errors in the oocytes’ genetics (specifically in the chromosomes) so that at 42 years of age we can find that up to 80% of the remaining oocytes have these alterations. For this reason, the risk of miscarriage increases and it would be advisable to carry out an early ultrasound scan in the first trimester (between 8-10 weeks) to assess viability at an early stage and not wait for the screening ultrasound scan at 12-13 weeks.

In order to find out as soon as possible whether our pregnancy is at risk of chromosomal alterations, there is the possibility of carrying out a foetal DNA test in maternal blood, which can be used to detect anomalies at an early stage. Any abnormal results should be accompanied by appropriate genetic counselling by specialised professionals.

Age also influences an increased risk of gestational diabetes, which is why the so-called “sugar test” (O’Sullivan test in most protocols) is recommended in the first trimester in these cases.

Second and third trimester monitoring

Increasing maternal age has also been correlated with an increase in the percentage of cardiac malformations found, so special emphasis should be placed on the heart when performing the morphological ultrasound in weeks 20-22.

The increased risk of pre-eclampsia with age means that we need to monitor blood pressure during these trimesters, as well as verify through ultrasound that the baby’s growth is correct.

In addition, the “sugar test” has to be repeated as in all pregnancies in the second trimester as the risk is higher than in the first trimester due to the increase, among other hormones, of placental lactogen.

There is still much debate about the final management of these patients in the last weeks of pregnancy. Some advocate increased monitoring from the 38th week with cardiotocographic recordings and ultrasound, although no improvement in obstetric outcomes has been demonstrated. This debate extends to the end of pregnancy as we know that age predisposes to complications beyond 40 weeks of pregnancy. For all these reasons, it is very important to have a personalised follow-up that takes into account the characteristics of the pregnancy and the pregnant woman, as well as her wishes and opinions.

Dr María Martinez (MD associate No. 03/2870742), gynaecologist at Instituto Bernabeu