Low Risk Obstetrics | Catherine Elliot

PRE-CONCEPTION: planning a future pregnancy.

Even if you are healthy it may be important to discuss your plans to conceive with your gynecologist or health care provider.
You should start taking a folate supplementation (at least 400ug per day) at least 8 weeks prior to conceiving, and you may need to consider a vaccination 2 months prior to pregnancy, against German measles (rubella) if you are tested and you are not immune.
If you suffer from a chronic illness, the your treatment may need to be optimized, medication changed, or tests conducted to review the safety of a future pregnancy.

FIRST TRIMESTER : Congratulations on your pregnancy

Fortunately most newborns and moms and healthy, and this is likely to be the case with you. You may wish to read what is set out below. This includes details of each aspect of the appointments during the next 9 months.

The first appointment – 7-10 weeks

In pregnancy, the age of the embryo is counted in weeks from the first day of the last normal menstrual period and corresponds to about two additional weeks from the date of conception.

40 weeks is full term.

Measuring the crown rump length of the fetus at 10-14 weeks is the most reliable way to date a pregnancy, hence this is the a good time to book an appointment provided there are no concerns.

Accurately determining the expected date of delivery (due date; EDD) in the first trimester is vital and this EDD should not be changed, although the baby may be delivered before this date due to medical indications, or spontaneous labour.

At each visit to the midwife or obstetrician, the growth of the baby is assessed and plotted on a growth chart, and care should be taken to determine that the baby is growing along its growth chart.

Baby’s growth can be assessed by measuring the growing abdomen of the mother (symphysis-fundal height) or by way of an ultrasound, which measures the head, abdomen and femur length of the fetus to determine an estimated fetal weight.

Screening for chromosomal abnormalities:

The 12-13 week NT scan

This scan is one of the more important scans in your pregnancy.

Over last 15 years or so the management of the course of pregnancy has changed and more emphysis has been placed on the first trimester (conception -12 weeks) and the opportunity this appointment affords to allow for the prediction and prevention of complications later on in the pregnancy.

At the NT scan, features of this scan are used to determine whether there is a high risk (chance) that the baby is affected by a genetic problem, (trisomy 21, 13 or 18- see below) that the pregnancy is complicated by blood pressure problems, or whether there is a chance of a preterm delivery.

At this scan the nuchal translucency measurement is determined.

The nuchal translucency measurement is the measurement of the collection of fluid under the skin behind the fetal neck. All babies have some fluid to measure.

This measurement is then used, along with other features on the ultrasound, the hormonal blood tests, (PAPP-A and BHCG) and the age of the mother, to determine a risk for 3 chromosomal abnormalities: Trisomy 21 (Downs syndrome) Trisomy 18 and Trisomy 13. A thick NT measurement may also alert us to the fact that the fetus may be suffering from other conditions, such as Turners Syndrome or heart defects.

Downs syndrome is also called Trisomy 21 and means there is an extra chromosome (number 21). Instead of having two chromosomes at number 21, there is an extra (third) chromosome. The degree to which each child with Downs syndrome is affected is variable.

The NT scan is what is known as a screening test. Screening tests don’t tell you for definite if your baby has Downs syndrome- they tell you how likely it is that your baby might have it. This means that a “low risk” result at the NT scan does not exclude Downs syndrome all together, but this is the first step to determining whether the fetus is “at risk” of having this problem.

To be able to diagnose a genetic abnormality we would have to test the chromosomes of the baby by way of a chorionic villous sample or an amniocentesis. This is a procedure where we extract fluid form around the baby using a needle into the uterus and send this for analysis. Because this procedure is invasive and carries a risk of miscarriage we would only perform this in cases where the risk of a genetic problem is high and where the parents would wish to test.

In addition to the NT screening test, some defects (albeit rare) can be detected at the first trimester scan, whilst others are more difficult to detect and some are impossible to document at 12-13 weeks. These are best looked for at the structural 20-22 week fetal anomaly scan.

FETAL ANOMALY SCAN

This scan is performed at 20-22 weeks.

In most cases the baby and mom are healthy, however this scan is important to assess the fetus for structural anatomical abnormalities that may or may not require further testing or diagnosis, and in the event of an abnormality being detected, to plan neonatal care after delivery .

Detailed review of all the fetal organs, the growth, the placenta and mouth of the womb (cervix) are all assessed at this scan.
This detailed anatomy scan remains the standard of care even though some major structural abnormalities may be detected earlier in the pregnancy.

MONTHLY APPOINTMENTS

After the 20 week fetal anatomy scan you should visit every month. Blood pressure, urine test is done and the growth of the baby is assessed.

At each visit to the midwife or obstetrician the growth of the baby is assessed and plotted on a growth chart, and care should be taken to determine that the baby is growing along its growth chart.

Birth weights may vary, but it is important to determine that your baby is indeed the weight it is destined to be and not smaller or larger.

Baby’s growth can be assessed by measuring the growing abdomen of the mother (symphysis-fundal height) or by way of an ultrasound, which measures the head, abdomen and femur (thigh bone) length of the fetus to determine an estimated fetal weight.

At each visit it is important to discuss the wellbeing of mom and baby and to explore the birth plans.

39-40 WEEKS

When you have reached full term and you have not yet delivered, it is important to assess the well-being of your baby in detail to determine if it is safe to continue the pregnancy and await labour. At this appointment we would discuss the options of inducing labour is the pregnancy continued into the 42 week.

POSTPARTUM

There are two recommended postnatal appointments.

10 days after delivery, to assess how the feeding is going, the healing of a caesarean section wound or vaginal tear.

6 weeks after delivery. At this it is an important to do a papsmear and discuss contraception (If this has not discussed prior to this appointment)

It is important to contact your health care provider if you are struggling, feeling unwell, if you are concerned about any aspect of your recovery.


I wish you all the best in your pregnancy journey.

Compiled by Dr Catherine Elliott