Just as in boys with sickle cell, puberty and the teenage growth spurt are delayed in girls with sickle cell disease. In particular, the age at which a girl has her first period may be delayed by 1-3 years compared with girls of the same age without sickle cell. Once the monthly menstrual cycle is established however the pattern is the same as in other women. There is no evidence that over all fertility is reduced in women with sickle cell. The number of pregnancies that women with sickle cell have is less than the number in women without sickle cell, but there are many possible reasons for this. The fewer number of pregnancies does not, in itself, mean that women with sickle cell have more difficulty in becoming pregnant.
The main reproductive issues facing women with sickle cell are the association of crisis pain with the menstrual cycle, the choice of contraception and pregnancy.
Crisis pain associated with the menstrual cycle occurs in a proportion of women with sickle cell, maybe in as many as one third. Typically, the pain is predictable and occurs at the same time in each monthly cycle, usually just before or with the period itself. The crises are presumably triggered by the variation in the levels of the female hormones, oestrogen and progesterone, which occur naturally during a normal cycle.
Sometimes period associated crisis pain can be averted by starting to take a non-steroidal anti-inflammatory drug (NSAID), such as ibuprofen, on a regular basis, starting just before the pain would be expected to begin and continuing until the end of the period. But a better option is to suppress the changes in the hormone levels which trigger the crisis, by taking some form of hormonal contraceptive treatment. This may be a combined oral contraceptive pill (OCP), containing a low dose of oestrogen, or a progesterone only preparation. If you think that you have crises associated with your periods then it is important to discuss this with your specialist, who can advise you about the best course of action.
Contraception or family planning is vitally important to women with sickle cell disease, because pregnancy and delivery carry significant risks, both to the mother and the baby and ideally pregnancies should be planned well in advance. You should have time to discuss all the issues fully with your specialist doctor and only go ahead when you understand what interventions and treatments may be needed to ensure the best chance of a successful outcome. Unfortunately, this is often not the case. The incidence of unplanned pregnancies in women with sickle cell is significantly higher than the incidence in other groups of women and, at least one reason for this, is that women with sickle cell often do not have easy access to good advice about family planning.
There are many different methods of contraception, some of which are more effective than others, and the choice is a personnel one. Barrier methods such as male or female condoms, cervical caps or diaphragms and contraceptive or spermicidal jelly can all be used in sickle cell disease without any risk, although they are of variable effectiveness. Intra-uterine devices, such as the coil, can also be used, but some doctors are cautious about these, because a coil may cause increased bleeding at the time of a period which can lead to severe anaemia in a woman who is already anaemic because of her sickle cell. Also, there is an increased risk of infection associated with intra-uterine devices and this may increase the risk of having a painful crisis.
Hormonal contraception is probably the most effective form available and there is no evidence that this causes any more problems in women with sickle cell than in any other groups of women. Despite this, the manufacturers of hormonal contraceptives still say in their product literature that these preparations should be used with caution in sickle cell, and this has made many doctors reluctant to prescribe these drugs. It is worth therefore saying again that there is no scientific evidence to support this statement and, if you want to use a form of hormonal contraception, then there is no reason why you should not do so. The choice is between a combined OCP, containing a low dose of oestrogen, or progesterone only preparations, which may be in the form of a daily pill, regular three monthly injections or a long acting implanted device. Best to talk with your specialist doctor or to a family planning clinic to make the best choice for you.
One of the main risks associated with the use of hormonal contraception is the increased incidence of blood clots affecting the veins, these are known as deep vein thrombosis (DVT) or pulmonary embolism (PE). The latter, where blood clots travel through the circulation to the lungs, can be very serious and even fatal. People with sickle cell already have an increased risk of DVT and PE for many reasons. They are often ill and immobile in bed, they have a focus of inflammation, namely the site of the painful crisis and they may have cannulae or other devices in their veins, all of which increase the risks of clots. For this reason many patients with sickle cell are given clot prevention treatment routinely, with daily injections of low molecular weight heparin (LMWH), when they are admitted to hospital. If you take some form of hormonal contraception and are hospitalised with a crisis or for surgery make sure you tell the doctors looking after you about the contraception you use, because in these circumstances it is even more important to have treatment with LMWH to protect you against the risk of a DVT or PE whilst you are ill.
Pregnancy poses increased risks both for the baby and for the mother with sickle cell disease and should be carefully planned after discussion with your specialist doctor. Although most women go through pregnancy uneventfully, it is very important that your care during pregnancy is shared between your haematologist and an obstetrician who is experienced in the care of women with sickle cell disease, to ensure the best outcome.
Before you become pregnant or have a baby, it is often very difficult to imagine what life with a little baby might be like, but this is one of the most important things to think about and to plan for. Looking after a small baby is exhausting and one of the most difficult tasks any of us will ever undertake. We all need help with this and if you have sickle cell the need for help and support is even greater. How will you manage your sickle cell disease and still look after a baby? Who will look after your baby or toddler if you have to be admitted to hospital with a crisis? Can you rely on your partner for this? Is your mother/sister/aunt available to help in those difficult early weeks and months? Do you have a network of trusted family and friends who will support you and your baby over the years. These are all important questions to think about before you decide to start a family.
When you have decided to go ahead one of the first things to consider is the genetic risk to the baby you are planning. If you have sickle cell anaemia (Hb SS) and your partner is a carrier for sickle cell (Hb AS), then there is a 50% chance, or 1 in 2 chance, that any baby you have together with also have sickle cell disease. Even in these liberated times childcare is mainly the responsibility of the mother and you need to decide whether or not you would want to bring up a baby with sickle cell. In order to answer this question you must know whether your partner has normal blood (Hb AA) or is a carrier for sickle cell (sickle cell trait or Hb AS). The only way to know this information is for your partner to have a special blood test, you should discuss the situation with him and make sure that he has this done. Your haematologist, his general practitioner or the local sickle cell centre will arrange this for him. If your partner’s blood is normal (Hb AA) you do not need to worry about this anymore, your baby will be a carrier for sickle cell and will be completely healthy. However, if your partner is a carrier for sickle cell himself (Hb AS) then you may want to consider the option of pre-natal diagnosis.
Pre-natal diagnosis means establishing the sickle cell type of your baby within the first few weeks of pregnancy. If the baby is shown to have sickle cell disease, and you are clear that you would not want to have a baby with the condition, then there is the option of having an abortion to terminate the pregnancy. This approach is not acceptable to many couples, but it does offer a way of having a healthy family to those who can accept it. The sickle cell type of the baby is established by taking a small piece of placental tissue, using a biopsy needle inserted through the stomach wall of the mother. This is usually done at about 10-12 weeks gestation and is generally very safe, although there is a small risk of miscarriage after the procedure of about 2%. The tissue is analysed by DNA technology and the answer is usually available within 7 days. If the baby has sickle cell disease it is then possible to have an early termination. Whether or not you have pre-natal diagnosis it is very important to make sure that the doctors test your baby’s blood as soon as it is born, so that you know for certain whether your baby has sickle cell trait or sickle cell disease.
The main problem for the baby being carried by a woman with sickle cell disease, is that the placenta, which feeds the baby throughout pregnancy, can be affected by sickling. If this happens the placenta fails to work properly and as a result the baby does not get enough food and does not grow in the normal way. This is called intra-uterine growth retardation (IUGR) and usually begins sometime after 25 weeks gestation, or about two thirds of the way through the pregnancy. Your obstetrician will ensure that you have regular ultrasound scans during pregnancy, which accurately measure the size of the baby, and which also measure how fast the blood circulates through the placenta. A slow down in the baby’s rate of growth or a decrease in placental blood flow are both early signs of IUGR. Sometimes IUGR can be prevented or delayed by starting a programme of regular exchange blood transfusions, however if the pregnancy is near term, your obstetrician might decide that the best way forward would be to deliver the baby early, so that it can then be given enough food to allow it to grow normally again.
For the woman with sickle cell there are many potential problems during pregnancy. One study suggested that 50-70% of women are admitted to hospital at some point during their pregnancy. The team looking after you will attempt to predict some of the problems by arranging screening investigations when you first book in the antenatal clinic. These may include an echocardiogram, to detect asymptomatic high blood pressure in the lungs (pulmonary hypertension), examination of the eyes to detect damage to the retina (sickle cell retinopathy) and tests on the urine to exclude early problems with the kidneys. You will also be seen frequently during the pregnancy, initially every 4 weeks and towards the end every 1-2 weeks.
Painful crises tend to increase in frequency, particularly towards the end of the pregnancy and in the first weeks after the baby is born. A crisis should be treated in the same during pregnancy, although it is best to avoid taking non-steroidal anti-inflammatory drugs (NSAIDs), like ibuprofen, during pregnancy because they can harm the baby. Dehydration, due to pregnancy associated nausea and vomiting, resulting in a crisis can be a problem and may require admission to hospital for intravenous fluids. All pregnant women become anaemic and, because women with sickle cell start pregnancy with a lower haemoglobin level than normal, their anaemia may become very severe and require a “top up” blood transfusion; this may be necessary in 30-40% of women. Make sure that you take your folic acid regularly during pregnancy, as this will maximise your haemoglobin level, but do not routinely take iron supplements. Iron deficiency is uncommon in women with sickle cell so only take iron tablets if your doctor tells you that you have definitely become short of iron. Other drug treatments sometimes prescribed during pregnancy include aspirin, to reduce the risk of high blood pressure, or pre-eclampsia, and LMWH injections if there is a previous history of DVT or PE.
Provided the baby has grown well during pregnancy and there is no evidence of IUGR, your obstetrician will probably advise that labour should be induced at about 38 weeks gestation, 2 weeks before the normal date of delivery. This is because there is a very small risk of the baby dying suddenly and unexpectedly right at the end of the pregnancy, this is called a stillbirth. Early delivery avoids this devastating complication. During labour you will be given additional fluids into a vein, as it is very difficult to remember to drink enough during labour and after the baby has been born. You will also be given extra oxygen if your oxygen levels are low for any reason. These two simple precautions are to try and avoid the onset of a crisis. The doctors will cross match your blood so that blood for transfusion is available should you need it and they will monitor your haemoglobin level carefully. Once the baby has been born you will be kept in hospital until any risk of infection has passed, your haemoglobin level is stable and any sickle cell pains have resolved. Don’t forget to make sure that the doctors have taken a blood sample from your baby to confirm it’s sickle cell type before you go home.