The 1st Trimester of Pregnancy

Clinical controls in the first trimester of pregnancy

Pregnancy tests follow a very strict protocol so that the process ends successfully, for both the mother and the fetus. Skipping them carries unnecessary risks since they can detect and prevent numerous maternal-fetal health problems. But what does this close monitoring consist of? It is based on a triple control: clinical, which consists of going to medical visits; analytical, which involves undergoing several analyzes every quarter; and ultrasound, which includes the performance of three ultrasounds.

Every pregnant woman should start pregnancy control from week seven or eight. This clinical examination includes a monthly visit to the doctor, in which the weight, the arterial tension and the proteins of the urine are monitored. Detection of high blood pressure levels and elevated levels of albumin in the urine would indicate that the woman may have developed gestational hypertension, which would require further analysis. The professional also talks to the pregnant woman to probe how she is, performs an abdominal examination, listens to the fetal heartbeat, measures the uterine height and checks the placement of the fetus.

First trimester: rule out infections and abnormalities

In the first trimester, an analysis is performed to find out the mother’s blood group and her RH factor. A blood count (global count and percentages of the three basic types of cells and their morphology) is performed, a urinalysis to rule out infections and infectious disease serologies that may be relevant to the good course of pregnancy and the development of the fetus. It is essential to detect early if the pregnant woman is carrying one of them.

The “Toxoplasma gondii” is the parasite that causes toxoplasmosis, which originates, above all, from eating raw or undercooked meat or derivatives that contain parasite cysts. Contaminated water, soil, or vegetables are the second source of infection, while contact with domestic cats is considered a low-risk factor. Its prevalence in women of childbearing age is highly variable, between 15% and 77%. Its detection is important because 15% of infected fetuses are symptomatic at birth from diseases contracted before 24 weeks. They may experience hydrocephalus, intracranial calcifications, chorioretinitis, and seizures, although only 4% have permanent neurologic sequelae, death, or bilateral blindness.

Hepatitis B and C. Pregnancy is a good opportunity to do a population screening for hepatitis B virus (HBV), since vertical transmission (from mother to baby) is very high, up to 80%, if the HBe antigen is positive. In negative cases, this figure is between 10% and 25%. To prevent it, specific gamma globulins are administered and newborns are immediately vaccinated. Regardless, 10% of babies born to mothers with HBe-positive antigens can be infected. As for chronic HCV infection, the risk of vertical transmission is close to 5%.

Syphilis is a systemic infection caused by “Treponema pallidum”, which has two transmission routes: sexual and placental. In recent years, there has been a significant increase in cases, which is why gestational screening is key. The risk of intrauterine transmission occurs from 14 weeks of gestation and increases progressively. If the affected pregnant woman is not treated with penicillin and intrauterine transmission occurs, the result is 40% of miscarriages or perinatal deaths and 40% of children will be born with congenital syphilis. Only the remaining 20% ​​will not get sick, says Sandra Hernández, a specialist in Gynecology and Obstetrics at the Department of Maternal-Fetal Medicine of the Clinical Institute of Gynecology, Obstetrics and Neonatology at the Hospital Clínico de Barcelona.

Rubella is a respiratory transmission infection caused by a virus of the family “Togaviridae”. The current vaccination program in Spain is carried out through two doses of the MMR vaccine and has provided lifelong immunity in 95% of cases. For this reason, it has been almost completely eradicated, with exceptional cases of congenital infection, generally imported from countries without routine vaccination. Congenital rubella is a chronic infection with serious late-onset sequelae to the fetus, including heart disease, ophthalmopathy, deafness, and microcephaly.

HIV. In recent years, the vertical hauling of this virus has decreased and is less than 1% thanks to its detection in pregnancy. Although the virus can cross the placenta at any time and infect the baby, the greatest risk occurs in the weeks before and during transmission. If the pregnant woman is seropositive, an antiretroviral is administered during the weeks before transmission to cut down the risk of infecting the baby.