Understanding Miscarriage

There are high social expectations and strong cultural beliefs about it being our right to our own choice of when to have a baby (choice = empowerment). We also expect the pregnancy will end in a healthy, normal, live birth. Medical professionals do not usually talk/warn about miscarriage to their patients. With the advancement of scanning technology, pregnancies can be confirmed earlier. This means women can see their baby and bonding occurs earlier too. When a miscarriage happens unexpectedly, it can be a shocking end to the dreams and expectations of the woman and her partner.

Quote from Dr. Karen Buckingham, an Auckland obstetrician and gynaecologist: ‘And because human pregnancy is a relatively inefficient process, approximately 50% of all conceptions fail – with most miscarriages going unrecog­nised because they occur before or with a woman’s next expected period.’ (Next Magazine June 2012.)

Spontaneous abortion

The World Health Organisation defines miscarriage as ‘the spontaneous abortion of an embryo or fetus weighing 500 grams or less. This typically corresponds to a fetal gestational age of 20 to 22 weeks or less’. Miscarriage in New Zealand is defined as a pregnancy that ends spontaneously before 20 weeks. The baby not usually being born alive and weighing under 400g.

Just knowing 70% of fertilized eggs die before they are 6 days old can help in understanding miscarriage. As we learn about conception and the critical stages of a baby’s development (e.g. A 3 week old embryo has formed the cells that control the beat of the heart) and how much else can go wrong, we can further appreciate what a little miracle a baby really is.

Miscarriage affects one in every four women. The highest risk period is between 4 and 6 weeks. Once 8 or 9 weeks are reached and the baby’s heart beat is seen on a scan there is only a 4% to 5% chance of miscarriage, depending on the speed of the heart-beat. It should be 120 to 160 times per minute. (BMP) The risk then drops to between 5% and 8% and continues to drop as the pregnancy proceeds.

99% of foetal deaths occur in the first 12 to 14 weeks of pregnancy (1st trimester), although the actual miscarriage may not happen for some weeks after the baby dies. Medically this is called a ‘missed abortion’. (The baby is an “embryo” to the 8th week and a “foetus” after that.)

The chance of losing a first pregnancy is greater than later ones. 70% of miscarriages are unexplained.

What happens during miscarriage?

The symptoms you experience will depend on the cause of the miscarriage and how advanced the pregnancy is/was so may take hours, days or even weeks to complete. Usually the foetus, placenta and blood from the uterus leave the body through the vagina. (see ‘the miscarriage process’) You may discover during a routine scan that there is no heartbeat, or even an empty foetal sac. Usually, by the time bleeding begins your baby has already died. The exception is around the 6 weeks mark when only a small amount of blood is lost, then there is an 80% your baby will be fine (see ‘threatening miscarriage’).