30 weeks and 6 days pregnant
Here the baby is resting on the placenta, seen at the right-hand side of the image, with the umbilical cord just below the baby’s chin. The eyes are closed and this image was taken at a time when the baby was at his quietest, during deep sleep.
Once your baby’s production of red blood cells is in full swing, in theory your immune system could begin to harm your baby.
At 30 weeks your baby’s red blood cell production switches from the liver to the bone marrow. These red blood cells are unlikely to be of the same blood group as your own. Small numbers of these red blood cells often leak across the placenta; your body recognizes them as foreign and attacks them.
Your blood group is not important because, although antibodies to blood groups A, B, AB, or O attack your baby’s cells in your circulation, they are too large to cross the placenta and attack your baby. Therefore differences in ABO blood groups do not matter. However, everyone is also rhesus positive (85 per cent) or negative (15 per cent). If you are rhesus negative and your partner is rhesus positive, your baby may also be rhesus positive.
Rhesus negative women produce antibodies to rhesus positive blood cells; these are smaller than ABO antibodies and can cross the placenta. Once they do, large numbers of antibodies can attack your baby’s blood cells, leading to anaemia. First pregnancies are rarely affected. In a second pregnancy a rhesus negative woman is given one or two injections of the rhesus antibody “anti-D” in the third trimester. Anti-D is in a form that is too large to cross the placenta. This mops up any of your baby’s blood cells in your circulation, preventing your immune system from attacking your baby.
Your baby excretes and reabsorbs about 0.5 litre (18fl oz) of urine daily, and the amniotic fluid reaches a peak volume of about 1 litre (35fl oz) at 33 weeks. After this time the volume starts to decline and can be as little as 100–200ml (3.5–7fl oz) in an overdue pregnancy.
Low levels of amniotic fluid, known as oligohydramnios, can be a sign of a growth-restricted baby or a baby with kidney problems. Excessive amniotic fluid, known as polyhydramnios, may be seen in twin or triplet pregnancies, and is also associated with physical abnormalities in the baby or diabetes in the mother.
After 40 weeks, the fluid level needs to be checked regularly to ensure that there is not too steep a decline in fluid levels. If the overdue baby is thought to be at risk, an induction will be recommended.
Insomnia is a common problem during pregnancy and can lead to fatigue, feelings of stress and anxiety, and irritability.
The herbal teas valerian and passiflora are both safe during pregnancy, and can be drunk before bed to relax and encourage sleep.
Essential oils of lavender and Roman camomile can be added to the bath, or dropped on to your pillow, to calm and relax.
The homeopathic remedies Passiflora 6C, Coffea cruda 6C, and Nux vomica 6C are all good for sleep problems, and can be taken before bed and if you wake up during the night.
Bach flower remedies can relieve stress and aid sleep.