Advice
Dietary
Supplements
Habits
When to see the doctor
Risks in the First Trimester
These risks include:
Tests in the First Trimester
Routine tests
1. Blood and urine tests – we require 4 tubes of blood and 1 urine sample to perform these tests
a) Full blood count (FBC) – screens fo anaemia and thalassaemia. Tests for anaemia (haemoglobin level less than 11.5 g / dl), alpha- or beta- thalassaemia (MCV less than 80 fl is a good screening test). Haemoglobin electrophoresis is indicated if MCV is less than 80 fl, and would include the FBC and haemoglobin electrophoresis of the partner as well. DNA gene probes for thalassaemia may be indicated if alpha thalassaemia is suspected.
b) Infection screen for Hepatitis B, syphilis and HIV. If positive, there are strategies to reduce the risk of transmission of the infection to the baby.
c) Immunity screen for Rubella - If negative, consider rubella vaccination before the next pregnancy. It prevents the potential of contracting rubella during the first or second trimester of pregnancy that may affect the fetus severely.
d) Pre-exisiting diabetes mellitus – glucose and HbA1c levels.
e) Blood group and Rhesus type - This screens for Rhesus negative state in the mother. If the mother is Rhesus negative, injection with Rhogam injections during certain scenarios would reduce the risk of a blood problem to future, or even current, babies.
f) Screening for antibodies to atypical red blood cell antigens - This screens for potentially harmful antibodies in the mother that could cross the placenta and bind to the red blood cells of the fetus and possibly causing heart failure in the foetus, and also possible antibodies that may cause a reaction if an incompatible blood type is used for blood transfusion.
g) Screen for asymptomatic urinary tract infection with urine microscopy. If it shows possibility of urinary tract infection, a urine culture would be indicated and antibiotics may be necessary as it may reduce the risk of late miscarriages and preterm labour.
2. First Trimester Scan (FTS) between 11-13 weeks
The FTS is designed to screen for 4 groups of problems in pregnancy:
a) Risks of common chromosomal abnormalities (including Down syndrome [Trisomy 21], Edward syndrome [Trisomy 18] and Patau syndrome [Trisomy 13]) using Fetal Medicine Foundation (FMF) software. This allows the detection of 80% of Down syndrome, 90% of Edward syndrome and 90% of Patau syndrome.
b) Early structural abnormalities such as anencephaly (absence of skull), exomphalos (protrusion of intestines through an abdominal wall defect), megacystis (enlarged bladder), etc.
c) Risk of early pre-eclampsia requiring delivery 34 weeks (i.e. a serious condition during pregnancy characterised by high blood pressure with proteins in the urine). If left untreated, pre-eclampsia tends to progress and may become very serious. As the treatment of pre-eclampsia is delivery, we are most worried if the pre-eclampsia occurs early (i.e. before 34 weeks) which may require us to delivery early. If the risk of pre-eclampsia is raised, calcium supplementation of at least 1 g / day and low dose aspirin of 100-150 mg taken in the night may reduce the risk of this complication from 0.4% of the population to 0.04% of the population.
d) Risk of fetal growth restriction before 37 weeks which may require early delivery. If fetal growth restriction is detection, the fetus needs to be closely monitored with fetal movement chart, regular measurements of the fetus and regular Doppler studies of the blood flow within the baby, and also cardiotocography (CTG) later in the third trimester. When the fetal status is non-reassuring, early delivery may be indicated. Low dose aspirin and calcium supplementation of at least 1 g / day may reduce the risk of fetal growth restriction. However, there is less data on low dose aspirin for this condition.
Further tests for chromosomal abnormalities
One needs to understand the different types of chromosomal abnormalities to decide which tests to do.
1. Large chromosomal abnormalities that are visible to the microscope are at least 5-10 MB in size.
Figure - Conventional chromosomal culture showing 46XX and 46XY.
a) Common chromosomal abnormalities increase with increasing mother's age
i) Trisomy 21 or Down syndrome - It ranges from mild to severe, with normal lifespan for the mild cases, with mild to severe intellectual disabilities and typical facial appearance, often with heart defects, and other abnormalities.
ii) Trisomy 18 and Trisomy 13 (Edwards and Patau syndromes) - Severe disorders with multiple abnormalities with > 90% dying while in the womb or within the first year of birth; < 10% survive longer than 1 year.
b) Sex chromosomal abnormalities (including 47XXX, 47 XXY, 47XYY) - Most of these individuals are normal, but some may have deficits in social or intellectual skills. Individuals with 47XXY are often infertile. Many experts question if there is a need to screen for this group of conditions.
c) Other chromosomal abnormalities - These are typically not detected by routine screening tests but are fortunately rare and account for < 30% of all the large chromosomal abnormalities.
2. Smaller chromosomal abnormalities are invisible to the microscope and range between 0.6 to 5-10 MB in size. These include microdeletion and microduplication syndromes. Depending on the specific condition, these may cause variable effects on the intellectual function, multiple structural abnormalities, and autistic spectrum disorders. Advances in technology now allow many conditions in this category to be diagnosed though some experts question if there is a need to screen for this group of conditions as many may not have severe abnormalities like the large chromosomal abnormalities. This group of disorders does not appear to vary with mother's age, and appears to occur at about 0.84% prevalence. This group includes:
a) 22q11.2 deletion syndrome - This is the commonest micro deletion syndrome, occurring in about 1:2000 pregnancies, also known as DiGeorge syndrome. It may be associated with mild to moderate intellectual disability and schizophrenia, heart abnormalities, feeding difficulties, problems with immunity, and low calcium levels.
b) 4 other common deletion syndromes - They include 1p36 deletion syndrome, Prader-Willi syndrome, Angelman syndrome and Cri-du-chat syndrome. These are relatively rare, accounting for about 1:5000 to 1:20000 pregnancies.
c) Other microdeletion or microduplication syndromes - they could be grouped into 2 groups:
i) abnormal - like the 5 described above, though the severity of the condition may range from mild to severe.
ii) variation of unknown significance (VUS) where parents' blood may have to be further checked. Depending on whether the parents also carry the same microdeletions / microduplications, referral to a geneticist is usually required to discuss the possible outcomes of the baby.
One could choose no further test (which may be appropriate especially if abortion is not an option), an invasive diagnostic test such as chorionic villus sampling or amniocentesis (which is associated with 0.1-0.3% risk of miscarriage from the procedure), or a screening blood test at 10-12 weeks which evaluates the risk further (allowing detection of some, especially the common ones, but not all) before deciding if an invasive test is necessary. The test to choose for this category depends on individuals’ views on this.
This is a suggestion of an algorithm that may help you choose which test to do.
Dietary
- To avoid toxoplasmosis, avoid raw meats (e.g. raw ground beef, rare lamb, uncooked pork), unpasteurised goat's milk, eating unwashed vegetables and fruits, and avoid handling cats' litter.
- To avoid listeriosis, drink only pasteurised or UHT milk, and avoid eating ripened soft cheese (e.g. Camembert, Brie or blue-veined cheese), pate, undercooked food.
- To avoid salmonella, avoid eating raw or partially cooked eggs or food that may contain them (e.g. some types of mayonnaise or mousses), and raw or partially cooked meat (e.g. poultry and shellfish).
- Go generous on fruits and vegetables.
- Fish is healthy but some health authorities have recommended pregnant women to eat no more than 2 portions of oily fish, such as mackerel or salmon, a week. This is because of too much mercury that may be found in oily fish can be harmful to an an unborn baby's development. Also avoid eating more than 2 fresh tuna steaks or 4 medium-sized cans of tuna a week, and avoid eating shark, swordfish or marlin.
- Avoid drinking too much alcohol - we know that alcohol binges may be associated with fetal alcohol syndrome in some patients, hence avoid alcohol or limit yourself to not more than 1 glass a day.
- Avoid coffee as recent studies show that too much coffee consumption may be associated with an increase in risk of miscarriage - limit yourself to 0-1 cup of coffee per day.
- Tea - There isn't any similar studies with tea but I would generalise the study to include tea as tea also contain caffeine and we don't really know if it is the caffeine or other constituents in the coffee that is associated with the increased risk of miscarriages.
Supplements
- Folate 0.4-5 mg every morning - this reduces the risk of fetal brain and spinal abnormalities e.g. anencephaly and spina bifida.
- Other multivitamins containing iron and calcium supplements - I generally avoid these till after 12 weeks as they may exacerbate nausea and vomiting which is rather common during the first trimester.
- DHA supplements - These are now quite popularly taken during pregnancy as DHA is an important constituent of the brain and the retina, and is thought to be useful for the development of the brain and retina in the fetus. I normally start on this from 12 weeks gestation.
Habits
- Avoid smoking
- Avoid certain medications - tell the GP that you are pregnant.
- Eat well - You may have to modify your meals to small frequent meals and actively avoid smells or foods that may cause you to have more nausea and vomiting during this period.
- Have regular physical activity 3-5 times a week - brisk walking and swimming are some good activities
- Sexual intercourse - in general, sexual intercourse does not cause complications unless there are risk factors e.g. bleeding during pregnancy, a low-lying placenta, high risk for preterm labour
When to see the doctor
- Have an ultrasound scan at about 6-7 weeks - this is to date the pregnancy accurately, to determine if it is one or more babies, and to confirm that the pregnancy is within the uterus (and not an ectopic pregnancy)
- Inform the doctor of any:
- family history of children with disabilities / genetic diseases
- vaginal bleeding and/or abdominal pain
Risks in the First Trimester
These risks include:
- Ectopic pregnancy - This occurs in 1% of pregnancies. This usually presents with vaginal bleeding with or without moderate to severe abdominal pain. This is a medical / surgical emergency
- Miscarriage - This occurs in 10-15% of pregnancies. It may present with vaginal bleeding with or without abdominal pain. It may also not be associated with any symptoms.
Tests in the First Trimester
Routine tests
1. Blood and urine tests – we require 4 tubes of blood and 1 urine sample to perform these tests
a) Full blood count (FBC) – screens fo anaemia and thalassaemia. Tests for anaemia (haemoglobin level less than 11.5 g / dl), alpha- or beta- thalassaemia (MCV less than 80 fl is a good screening test). Haemoglobin electrophoresis is indicated if MCV is less than 80 fl, and would include the FBC and haemoglobin electrophoresis of the partner as well. DNA gene probes for thalassaemia may be indicated if alpha thalassaemia is suspected.
b) Infection screen for Hepatitis B, syphilis and HIV. If positive, there are strategies to reduce the risk of transmission of the infection to the baby.
c) Immunity screen for Rubella - If negative, consider rubella vaccination before the next pregnancy. It prevents the potential of contracting rubella during the first or second trimester of pregnancy that may affect the fetus severely.
d) Pre-exisiting diabetes mellitus – glucose and HbA1c levels.
e) Blood group and Rhesus type - This screens for Rhesus negative state in the mother. If the mother is Rhesus negative, injection with Rhogam injections during certain scenarios would reduce the risk of a blood problem to future, or even current, babies.
f) Screening for antibodies to atypical red blood cell antigens - This screens for potentially harmful antibodies in the mother that could cross the placenta and bind to the red blood cells of the fetus and possibly causing heart failure in the foetus, and also possible antibodies that may cause a reaction if an incompatible blood type is used for blood transfusion.
g) Screen for asymptomatic urinary tract infection with urine microscopy. If it shows possibility of urinary tract infection, a urine culture would be indicated and antibiotics may be necessary as it may reduce the risk of late miscarriages and preterm labour.
2. First Trimester Scan (FTS) between 11-13 weeks
The FTS is designed to screen for 4 groups of problems in pregnancy:
a) Risks of common chromosomal abnormalities (including Down syndrome [Trisomy 21], Edward syndrome [Trisomy 18] and Patau syndrome [Trisomy 13]) using Fetal Medicine Foundation (FMF) software. This allows the detection of 80% of Down syndrome, 90% of Edward syndrome and 90% of Patau syndrome.
b) Early structural abnormalities such as anencephaly (absence of skull), exomphalos (protrusion of intestines through an abdominal wall defect), megacystis (enlarged bladder), etc.
c) Risk of early pre-eclampsia requiring delivery 34 weeks (i.e. a serious condition during pregnancy characterised by high blood pressure with proteins in the urine). If left untreated, pre-eclampsia tends to progress and may become very serious. As the treatment of pre-eclampsia is delivery, we are most worried if the pre-eclampsia occurs early (i.e. before 34 weeks) which may require us to delivery early. If the risk of pre-eclampsia is raised, calcium supplementation of at least 1 g / day and low dose aspirin of 100-150 mg taken in the night may reduce the risk of this complication from 0.4% of the population to 0.04% of the population.
d) Risk of fetal growth restriction before 37 weeks which may require early delivery. If fetal growth restriction is detection, the fetus needs to be closely monitored with fetal movement chart, regular measurements of the fetus and regular Doppler studies of the blood flow within the baby, and also cardiotocography (CTG) later in the third trimester. When the fetal status is non-reassuring, early delivery may be indicated. Low dose aspirin and calcium supplementation of at least 1 g / day may reduce the risk of fetal growth restriction. However, there is less data on low dose aspirin for this condition.
Further tests for chromosomal abnormalities
One needs to understand the different types of chromosomal abnormalities to decide which tests to do.
1. Large chromosomal abnormalities that are visible to the microscope are at least 5-10 MB in size.
Figure - Conventional chromosomal culture showing 46XX and 46XY.
a) Common chromosomal abnormalities increase with increasing mother's age
i) Trisomy 21 or Down syndrome - It ranges from mild to severe, with normal lifespan for the mild cases, with mild to severe intellectual disabilities and typical facial appearance, often with heart defects, and other abnormalities.
ii) Trisomy 18 and Trisomy 13 (Edwards and Patau syndromes) - Severe disorders with multiple abnormalities with > 90% dying while in the womb or within the first year of birth; < 10% survive longer than 1 year.
b) Sex chromosomal abnormalities (including 47XXX, 47 XXY, 47XYY) - Most of these individuals are normal, but some may have deficits in social or intellectual skills. Individuals with 47XXY are often infertile. Many experts question if there is a need to screen for this group of conditions.
c) Other chromosomal abnormalities - These are typically not detected by routine screening tests but are fortunately rare and account for < 30% of all the large chromosomal abnormalities.
2. Smaller chromosomal abnormalities are invisible to the microscope and range between 0.6 to 5-10 MB in size. These include microdeletion and microduplication syndromes. Depending on the specific condition, these may cause variable effects on the intellectual function, multiple structural abnormalities, and autistic spectrum disorders. Advances in technology now allow many conditions in this category to be diagnosed though some experts question if there is a need to screen for this group of conditions as many may not have severe abnormalities like the large chromosomal abnormalities. This group of disorders does not appear to vary with mother's age, and appears to occur at about 0.84% prevalence. This group includes:
a) 22q11.2 deletion syndrome - This is the commonest micro deletion syndrome, occurring in about 1:2000 pregnancies, also known as DiGeorge syndrome. It may be associated with mild to moderate intellectual disability and schizophrenia, heart abnormalities, feeding difficulties, problems with immunity, and low calcium levels.
b) 4 other common deletion syndromes - They include 1p36 deletion syndrome, Prader-Willi syndrome, Angelman syndrome and Cri-du-chat syndrome. These are relatively rare, accounting for about 1:5000 to 1:20000 pregnancies.
c) Other microdeletion or microduplication syndromes - they could be grouped into 2 groups:
i) abnormal - like the 5 described above, though the severity of the condition may range from mild to severe.
ii) variation of unknown significance (VUS) where parents' blood may have to be further checked. Depending on whether the parents also carry the same microdeletions / microduplications, referral to a geneticist is usually required to discuss the possible outcomes of the baby.
One could choose no further test (which may be appropriate especially if abortion is not an option), an invasive diagnostic test such as chorionic villus sampling or amniocentesis (which is associated with 0.1-0.3% risk of miscarriage from the procedure), or a screening blood test at 10-12 weeks which evaluates the risk further (allowing detection of some, especially the common ones, but not all) before deciding if an invasive test is necessary. The test to choose for this category depends on individuals’ views on this.
This is a suggestion of an algorithm that may help you choose which test to do.
Very informative.
ReplyDeleteRupa