Early pregnancy is a time for excitement, joy and hope. However, for some, it can also bring despair and grief, as this is a very delicate stage of pregnancy where problems could occur . Therefore, it is important to be able to recognise the signs and symptoms of potential complications in the early stages of pregnancy.
The age of pregnancy is traditionally calculated from the first day of the last menstrual period, even though the actual conception usually occurs 2 weeks after the last period. An internal (transvaginal) ultrasound scan is used to diagnose pregnancy or any complication at this early stage. Pregnancy is then divided into 3 trimesters, with the first trimester, classified as ‘early pregnancy’, being from conception to 14 weeks. The two most common complications during early pregnancy are miscarriage and ectopic pregnancy, and both can present with bleeding or tummy pain. However, in many cases the conditions may not cause any symptoms.
The limits of scans
Despite the improvement in resolution of the ultrasound scan machines and expertise in scanning, there is a physical limit to what one can see on these scans. This is particularly true in early pregnancy, specifically when we are talking about a sac or a baby measured in millimetres. This occasionally leads to other modalities, mainly being a blood test for the hormone human chorionic gonadotropin (more commonly called hCG) to be added to aid diagnosis. If one does not see a definitive pregnancy sac within the womb, the term ‘pregnancy of unknown location’ is used.
Usually the levels of hCG nearly doubles in 48 hours in a viable early pregnancy. If it is a failing pregnancy (miscarriage, or rarely, an ectopic pregnancy that is resolving spontaneously without treatment), the value will fall. If it neither doubles or falls enough, it could be an ectopic pregnancy.
Miscarriage
Miscarriage is a common condition, with about 20-30% of pregnancies ending with a miscarriage. The good news is that the chance of a recurrent miscarriage (having at least 3 consecutive ones) is extremely rare, less than 1%. Usually early miscarriage occurs because of a genetic or chromosomal problem, and may not necessarily mean there is a problem with either couple. Therefore, only if one is unfortunate enough to have a recurrent miscarriage, detailed investigation is done to find and hopefully rectify a cause.
A miscarriage is diagnosed if a sac has not grown in size in a week or is 25 mm or more in size, but nothing seen within. Generally, a sac is seen around 4 weeks, a yolk sac (ring like structure within the sac) at 5 weeks, a foetal pole (embryo or the baby) at 6 weeks and a heartbeat at 7 weeks. However, there may be minor variation in the timing. With twins there can be a delay as well. If there is a baby (embryo), 7 mm but no heart beat is seen or no growth in a week, a miscarriage is diagnosed. Occasionally there may be no bleeding and miscarriage is incidentally diagnosed at a routine scan, usually at 12 weeks. This is termed a missed miscarriage.
Bleeding in early pregnancy is also quite common. However, it usually ends up being implantation bleeding and isn’t harmful, but any bleeding needs to be investigated. This is done through an internal ultrasound scan. If there is bleeding but scan shows the pregnancy is OK, it is called a threatened miscarriage. Mostly these pregnancies will continue without problems. Occasionally, one may see a baby but no heart-beat, in which case if the size is less than 7 mm, the scan will need to be repeated in a week’s time. If there is not enough criteria to state whether the pregnancy will be viable or failed, it is termed a pregnancy of unknown viability.
Ectopic pregnancy
Ectopic pregnancy is a pregnancy that is not in the womb, but outside, commonly in the fallopian tube. All pregnancies start in the tube and then travels down into the womb to grow. Occasionally the embryo may implant in the tube itself and start growing. However, such pregnancies cannot grow much longer and in most cases rupture or bleed internally (in the abdomen- not visible outside). This can potentially be a life-threatening emergency and causes intense stomach pain. Although rare, such pregnancies can occur elsewhere, including the ovaries or in the cervix (neck of the womb).
Ectopic pregnancies can be detected through ultrasound scans and occasionally hormone levels. If detected early, ectopic pregnancies can be treated by a Methotrexate injection, or two in some rare cases, to the mother intramuscularly, or by keyhole (laparoscopic) surgery. If the other fallopian tube is normal, it may be better to remove the affected tube. This is because the ectopic pregnancy may have happened because of a damaged tube in the first place (from previous pelvic infections or surgery in the stomach region). Further surgery on the tube may damage it even more and increase the risk of another ectopic pregnancy. However, in some cases if the other tube is damaged or absent and one wants to preserve fertility, one can remove the pregnancy tissue only and save the tube. A patient in this case would need regular monitoring of her blood hCG levels until they return to normal, and there would be an increased risk of ectopic pregnancy in the future.
Molar pregnancy
A rare complication of early pregnancy is molar pregnancy. This occurs the tissues that would have formed the placenta (after-birth) grow abnormally. Rarely, an embryo may be present as well. After removal of the tissue surgically (by suction evacuation from below) and confirmation of the diagnosis under microscope, one would need regular follow up in dedicated centres and after any future pregnancies to detect recurrence.
