Tests carried out during pregnancy

July 2017

Blood tests

A urine test is remains the first test to confirm pregnancy, however, some doctors may request a blood test it can:

HCG hormone levels

Determine the HCG hormone levels which confirms the pregnancy and how well it is progressing

Knowing your blood group and Rhesus Negative

A rhesus (Rh) negative means that the mother can develop antibodies against her baby if it is Rh positive. It is not usually a problem in the first pregnancy.

If a mother is Rh negative an injection of Anti D is usually given to the mother within 72 hours of childbirth. In some units Anti D injections can be given at 28 and 34 weeks as well as after childbirth. There is no risk during the first pregnancy, but can be a problem for subsequent babies

The risk occurs during a pregnancy following a miscarriage or a termination. Your blood group will be confirmed in your first antenatal visit . Pregnant women will therefore be screened for abnormal antibodies during early pregnancy, during the 6th month of pregnancy and if she is known to be Rh negative and or if she has previously received a blood transfusion.

Detect Syphilis

Syphilis is a sexually transmitted infection, which if left untreated can lead to miscarriage and stillbirth.

Detect HIV (AIDS)

This test is not mandatory but strongly recommended and widely accepted by most pregnant women.

If you already have HIV then there is a 1 in 6 chance of your baby becoming infected. Getting an early diagnosis is therefore crucial as treatment can reduce the risk of transmission to your baby. The blood test is confidential and does affect your ability to obtain insurance.

For more information about HIV and AIDS


Check you are protected against hepatitis B

This blood test is taken as part of the routine antenatal blood tests. Hepatitis B is a virus that affects your liver and the infection is easily transmitted to the baby. Finding out if you have Hepatitis B or are a carrier allows the doctors to vaccinate the baby at birth and also other family members.

For more information about hepatitis


A full blood count

This blood test is performed at the beginning of your pregnancy and during the 6th month of your pregnancy. It is to detect if you are anaemic which is treated with iron and folic acid tablets.

Check your immunity to German measles (Rubella)

The presence of antibodies means that the mother is immune. German measles can causes fetal abnormalities in up to 90% of cases especially in the first 8 to 10 weeks. Ideally it is advised to check your immunity to Rubella before getting pregnant. If you do not have any antibodies then it is strongly advised to get vaccinated before conceiving.

During pregnancy a low or negative result requires vaccination after giving birth and measures must be taken to avoid coming into contact with anyone with the infection. If during your pregnancy you come into contact with anyone with German measles or develop a rash and you're not immune you must seek medical attention immediately.

Detecting Diabetes during pregnancy

Gestational diabetes occurs in approximately 1 in 400 pregnancies and some women will remain diabetic after delivery. If glucose is detected in your urine then an 'oral glucose tolerance test' (OGTT) is performed: -a venous blood sample is measured before and after a sugar drink and if glucose levels are raised then a diagnosis is made.

An OGTT test is also offered to women with risk factors (overweight, family history of diabetes, women aged over 40 years, women from Asia, North Africa, West Indies, with a history of fetal abnormality). Women who develop diabetes have a risk of delivering a bigger baby and having a more difficult delivery.

Detecting Down syndrome and other abnormalities

The alphafetoprotien (AFP) blood test along with ultrasound can help detect chromosomal and structural disorders. Conditions such as Down's syndrome, cystic fibrosis, dwarfism and spina bifida. The test is performed at about 15 weeks. High levels of AFP are associated with spina bifida and low levels can indicate a high risk of Down's syndrome. If Down's syndrome is suspected amniocentesis may be offered.

For more information about down's testing go to;

Urine Testing

A urine analysis may find
  • The presence of sugar, which can be indicative of gestational diabetes. Diabetes would be confirmed by a blood test.
  • The presence of protein (albumin) , may be a sign of high blood pressure (hypertension). Pregnancy induced hypertension or toxemia can cause severe complications.
  • Leucocytes and Nitrates can suggest the presence of bacteria indicating urinary infection, which must be treated.


Ultrasound examination is essential to check for defects, perform measurements of the baby and monitor growth. It's important to calculate the age of the baby, check the position of placenta, and see if there's more than one baby and for some parents to determine the sex of the child.

Seeing your baby for the first time during your 12 week ultrasound examination can be a special moment. It is during this examination that parents see their baby established in the womb and that its heart is beating.

It can also cause anxiety for some parents as they fear discovering defects and abnormalities.

Ultrasound is performed using an ultrasound probe which is put on the tummy of the mother. A gel is applied to the surface of the abdomen to facilitate the transmission of ultrasounds.

The emitted ultrasounds are reflected differently depending on tissue density. They are then converted into signals by a computer system and visualised onto a monitor as images.

All expectant mothers should be aware that ultrasound does not detect all abnormalities. No test is 100% accurate, therefore, it is important to realise that there is no guarantee all defects will be diagnosed.

Some fetal scanning units like you to have a full bladder before your scan because it offers a better picture quality.

Ultrasound - at what stage?

First ultrasound

The first ultrasound is recommended at 12 weeks of pregnancy. This ultrasound allows to
  • Check fetal development by obtaining measurements of the head, neck, length of body etc.
  • Know the exact date of pregnancy
  • Check for more than one baby
  • Detect certain malformations
  • Detect the risk of chromosomal abnormalities
  • Locate the placenta
  • Reassure the parents that the child is normal...

In some cases, a Doppler examination may be required: This test measures the flow in the blood vessels of the uterus and umbilical cord, the size of the umbilical cord from the uterine artery and or the cerebral artery of the fetus.

Second ultrasound

The second ultrasound, called ultrasound morphology, is scheduled between 20 and 22 weeks. It examines in detail the fetal anatomy. It helps identify defects.

It often identifies the baby's gender: up to 70% of couples want to know the sex of their unborn child. It helps to find the exact location of the placenta and assess fetal growth.

Additional ultrasounds

Occasionally additional ultrasounds are done from 24 weeks onwards to:
  • Monitor growth or abnormalities detected in earlier ultrasounds.
  • Check the position of the placenta
  • Clarify the position of the baby in the womb.

It is possible to perform an ultrasound at any time of pregnancy in cases of suspected abnormalities or if health of the mother is compromised.

Diagnostic ultrasound

When an abnormality is suspected during an ultrasound screening or if there is a significant risk of fetal abnormalities, a referral to a more specialist fetal scanning unit is required. Ultrasound is used when Chorionic Villus sampling (CVS) or Amniocentesis is required.

An ultrasound is safe performed under strict medical care and you should know that doing an ultrasound does not affect the fetus.

Private Ultrasounds

Beware of private companies that perform 'keepsake' ultrasound examinations. Ensure they have the appropriate equipment, are suitably qualified and are trained and experienced to carry out such examinations. Having an ultrasound for non-medical reasons is not recommended.

File created with the collaboration of Claire Gabillat


Examens pendant la grossesse - Prise de sang, etc.
Examens pendant la grossesse - Prise de sang, etc.
Exámenes en el embarazo
Exámenes en el embarazo
Latest update on November 13, 2013 at 08:23 AM by Crashounette.
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