Third trimester of pregnancy

Flying during pregnancy

It's perfectly safe to fly while you're pregnant, but you may need more room for comfort and the chance to walk around. Keep up your fluid levels by drinking plenty of water and do some leg and ankle exercises to maintain healthy blood circulation.

Some airlines restrict travel for pregnant women after a certain time, and you may only be able to get travel insurance up to 28 weeks of pregnancy.

If you're travelling after this time, the airline may ask for a letter from your doctor or midwife saying the pregnancy is straightforward and there's no reason in their view why you can't fly. Airlines have different policies, so always check first.

Premature babies and breathing

Very premature babies need help to breathe, and are at risk of respiratory distress syndrome (RDS). A preterm baby's lungs may not produce enough surfactant, which coats the inner surface of the air sacs and stops them collapsing when the baby breathes.

Preterm babies may be helped with a ventilator, and they're also given extra surfactant to make up for the fact that their lungs are still unable to produce it normally.

High blood pressure

This is sometimes referred to as pregnancy-induced hypertension, or PIH. Some women with high blood pressure develop pre-eclampsia, which causes protein in your urine and swelling. In some cases it becomes serious and affects other parts of the body, such as the liver, brain, lungs or blood clotting system, which can be serious.

PIH is more common with first babies, and its main significance is as a sign of pre-eclampsia, which can affect the efficiency of your placenta. Between five and 15 per cent of pregnant women develop PIH.

It can be treated with drugs, in the hope that lowering your blood pressure will reduce the risk of pre-eclampsia, but a recent review of the research indicated that it's not known if treatment works. If you've been diagnosed with PIH, take lots bed rest and relaxation.

Baby's head not engaging

The technical term for a baby and a pelvis that don't 'fit' together is cephalo-pelvic disproportion. This may be suspected if your baby's head hasn't engaged - although some babies heads don't engage in the pelvis until labour actually begins.

Some women produce a baby that's just a little too big for them, although in most cases nature 'matches' you and your baby. Small women tend to produce small babies.

If you have had disproportion in one pregnancy and had a caesarean because of it, it doesn't necessarily follow that subsequent pregnancies will go the same way.

Your perineum

This is the skin between your vagina and anus. It stretches against the pressure of your baby's head during the birth and needs to have a lot of 'give' so you don't tear.

Occasionally, the midwife will make a cut in the perineum, called an episiotomy, which is repaired by stitches after the birth. Small natural tears in the perineum are common and heal themselves. Larger tears require stitches.

When the head engages

This is sometimes compared to an egg fitting into an egg cup and it means your baby's head has dropped down and is now firmly fixed into your pelvis, ready for labour.

You may feel it from the top as the sensation known as 'lightening'. This is when the baby no longer presses against your diaphragm. Your breathing may also feel easier. On the other hand, you may feel slightly uncomfortable at the other end. Engagement is a sign that your baby is in a good position to be born.