Although fetal weight is increasing steadily (now approximately 1.4kg), growth in terms of length will start to slow down from this week onwards. Fetal length is around 40cm from crown to heel at this point of pregnancy and is unlikely to increase significantly before birth. In addition to this, both the lungs and digestive tract are almost fully developed now. The amniotic sac will be holding around a litre of amniotic fluid at this point, but this volume will decrease over the coming weeks, as there is less available space to accommodate it. Brain development also continues during this period and cognitive ability is increasing. The brain now has the appearance of an adult human brain, with characteristic grooves and wrinkles on the surface.
Sufficient body fat has now been laid down for the lanugo – the downy body hair – to start shedding. The fetus is also now able to partially control its own body temperature.
The fetus continues to open and close its eyes and the blinking reflex is becoming more refined. The fetus is able to distinguish light and dark and may even track an external moving light source with head movements or by attempting the grasp the light. Even at birth, vision is still underdeveloped and a newborn baby is only able to see a distance of around 25cm. Vision will continue to develop after birth and most children, with normal vision, do not achieve 20/20 vision (’perfect’ vision) until around the age of eight.
It is quite common for women to experience feelings of breathlessness at this stage of pregnancy. This is caused by the enlarged uterus exerting pressure on the diaphragm and restricting the ability of the lungs to expand. Although it may feel uncomfortable, it is normal. During the final weeks of pregnancy – usually from 34 weeks onwards – the baby’s head will move down into your pelvis, achieving the position for birth. This will create more space in your abdomen and make breathing easier. It may also help to alleviate digestive discomfort.
Some women begin to experience Braxton Hicks at this time. These are thought to be ‘practice’ contractions. Although most women report that they are painless, some women do find them painful. If you are concerned about the level of pain you are experiencing, you should consult your midwife.
Many women see the return of fatigue during the third trimester. This is due to the demands that the growing baby is putting on your body. There is no cure for fatigue, but getting plenty of rest and asking for help from friends and family can help. It is also common to experience bouts of constipation during this time due to the uterus putting pressure on the bowel. Ensuring that you drink plenty of fluids and eat a diet rich in fibre can both help to alleviate constipation.
Symptoms to watch out for
Pre-eclampsia, vaginal bleeding, premature birth and obstetric cholestasis are important complications in late pregnancy. Pre-eclampsia manifests as headaches, disturbances of vision, swelling particularly of the legs and face and upper abdominal pain. It can result in a small baby and the tummy being smaller than it should be. Vaginal haemorrhage (bleeding from the vagina) is abnormal in late pregnancy. Painful contractions can result in premature birth. Itching of the palms of the hands and the soles of the feet may be due to obstetric cholestasis which is a threat to the baby. More generalized itching is common and usually harmless.
Movements of the baby are important: there should be at least ten episodes a day.
What is routinely offered on NHS
Visits to the midwife or GP become more frequent in later pregnancy. She will ask about symptoms; taking the blood pressure and checking the urine. Referral will be made to the consultant as necessary. If there is a serious threat of early birth then an injection of steroids is given to the mother which will help to protect the baby from respiratory distress.
What other care is available
In a private self referral clinic additional blood tests and ultrasound scans can be done at short notice with rapid reporting of results. This is important if the baby is smaller than it should be or not moving enough. The woman and her partner can see a consultant for opinion and advice. This is done at a convenient time and with plenty time for discussion.
Private 1 to 1 antenatal birth preparation classes are available with senior midwives, whether or not you choose to deliver privately.