Second Trimester (13-23 weeks)

General Advice

1. This is the best time to travel. Plan your holiday around this time. The main risk in the first trimester is miscarriage and the main risk in the third trimester is preterm labour. In the second trimester, the risk of miscarriage is the smallest. It is also the time when the nausea and vomiting of the first trimester has subsided, and the increasing pressures symptoms of a uterus increasing in size in the third trimester have not set in.
2. This is a good time to find out more about:

• Vaginal delivery / Assisted vaginal delivery / Caesarean section (see page on Third Trimester)
• Labour and pain relief during labour (see page on Third Trimester)
• Cord blood banking (see section below)

Second Trimester Screening Scan or Fetal Anomaly Scan at 18-22 weeks

• Structural survey and measurements - This is a systematic screen of major structural abnormalities that can be detected with ultrasound scan, and a set of measurements based on a checklist. This would allow the majority of, but not all, structural abnormalities to be detected.
• Soft markers - These are often transient ultrasound markers or minor structural variations that when present could increase the risk of the fetus having Down syndrome or other chromosomal abnormalities.
• Placental location - If the placenta is low-lying at this stage, it is important to check on the placental location again in the third trimester as some of these cases may need to delivered by Caesarean section to prevent severe vaginal bleeding.
• Uterine arterial Doppler studies - A high resistance on the uterine arterial Doppler studies would predict a higher risk for pre-eclampsia (PE) and intrauterine growth restriction (IUGR).
• Cervical length - A long cervical length predicts a very low risk of preterm labour before 33 weeks, while a short cervical length predicts a slightly increased risk of preterm labour. A patient with short cervical length may need to be monitored more frequently for a further shortening of the cervical length and may benefit from daily vaginal pessaries of micronized progesterone. 

Vaccination in pregnancy

1. Influenza (Flu) vaccine

Benefits: 

Flu is more likely to cause severe illness (including lung infection) in pregnant women (especially those who are overweight) than in non-pregnant women. Viral influenza vaccination was associated with 50% reduction in confirmed influenza among women and their babies. There was, however, no clear difference between vaccinated and non-vaccinated women in miscarriage, premature labour, stillbirth, admission to hospital for infection for baby or mother.

Risks: 

Common side effects include pain and redness, swelling, headache, fever, nausea, muscle aches, fainting. 

Rare side effects includes generalized weakness or tingling sensations over the limbs and upper body. Studies have shown a risk of 1-2 of such cases per million people vaccinated. 

Schedule: 

It is recommended by authorities in many developed countries. This involves one dose of inactivated vaccine any time in pregnancy (consider doing so after 12 weeks). But it is not recommended if you have a history of nerve disorders and probably not a good idea during periods of active Zika transmission as the side-effects of the flu vaccine may mask the symptoms of Zika infection in the mother.

2. Tdap vaccine

Benefits: Protects the newborn baby between 0-6 months against whooping cough (pertussis) and tetanus. There has been a surge in whooping cough infections in newborn babies in recent years, and may result in admission to intensive care units in some of them. The immunity you get from the vaccine will pass to your baby through the placenta and provide protection for them until they are old enough to be vaccinated against whooping cough at 6 months old. Currently there isn't a single vaccine against whooping cough alone, so we use a combined vaccine (Tdap).

Risks: 

Minor side effects include pain and redness, swelling, headache, tiredness, nausea and vomiting, fever, sore joints, body aches. 

 Rare side effects include rash, swollen glands, severe allergic reaction estimated in 1:1,000,000 and will happen within a few minutes to a few hours after vaccination, and difficulty moving arm after vaccination. 

Schedule: 

It is recommended by authorities in many developed countries to be given at 16-32 weeks regardless of prior status. For patients going to deliver in countries where neonatal tetanus is still endemic (e.g. India), tetanus toxoid vaccinations for all pregnant women is recommended. The Tdap vaccine replaces the need for tetanus toxoid in such patients.

Cord Blood Banking vs Delayed umbilical cord clamping

Delayed umbilical cord clamping

The advantages of delayed umbilical cord clamping (at least 30-60 seconds after birth) in term babies include:

1. increase the haemoglobin level at birth

2. improve iron stores in the first several months of life, which may have a favourable effect on developmental outcomes

Additional advantages of delayed umbilical cord clamping in preterm babies include:

1. lower rates of necrotizing enterocolitis

2. lower rates of intraventricular haemorrhage

3. lower need for blood transfusion

The main disadvantage is a small increase in the rates of jaundice that requires phototherapy in infants. There is no increase in the risk of postpartum haemorrhage.

Public and private cord blood banking

The blood in the umbilical cord is a rich source of blood stem cells which have been successfully used in the treatment of blood-related cancers (e.g. leukaemia, lymphoma), immune and genetic diseases (e.g. metabolic diseases). Blood stem cells are primitive cells that can differentiate into white and red blood cells, and platelets. An alternative source of these blood stem cells are those obtained from the bone marrow or mobilized peripheral blood.

There are advantages to using umbilical cord blood stem cells as opposed to those from the bone marrow or mobilized peripheral blood:

1. lower risk of graft-vs-host disease

2. tissue typing at banking allows easier search for a match

3. immediate availability when required

4. safe and painless with minimal risk to the mother and baby

Public cord blood banking

1. This is more cost-effective than private cord blood banking. Donation to the public cord blood bank is free.

2. There is, however, a high rate of rejection (up to 70-80%) chiefly due to inadequate cell count. Where the cell count is inadequate for public cord blood banking but adequate for community cord blood banking, parents would be given an option to pay a fee to bank in for potential use by the family.

3. Patients who require the cord blood banking have to pay for the cord blood.

Private cord blood banking

1. This is not as cost-effective as public cord blood banking as the chance of using it is low.

2. The rate of rejection is very low.

3. For many of the established indications for treatment (e.g. leukaemia, lymphoma, genetic diseases), the affected individual would not be able to use his / her own stored cord blood. If there is a relative's blood that matches the individual, the cord blood may be used (if there is adequate cell count).

4. An individual's cord blood can be used for the treatment of autism and cerebral palsy. This is currently performed on an experimental basis.

Private cord tissue banking

There is also stem cells present in the Wharton's jelly of the cord tissue. These mesenchymal stem cells can differentiate into cells of a person's nervous system, sensory organs, circulatory tissues, skin, bone, cartilage and more tissues. Research is expanding very quickly which may allow such cells to be used to treat many other diseases e.g. heart and kidney disease, autoimmune diseases, multiple sclerosis, Alzheimer's disease, Parkinson's disease, wound healing and sport injuries. Treatments with cord tissues are currently still performed on an experimental basis.