Early pregnancy care - Clinical Tree

Learning Outcomes

After studying this chapter you should be able to:

Knowledge criteria

List the causes of bleeding and/or pain in early pregnancy.
Describe the epidemiology, aetiology and clinical features of:
- Miscarriage
- Ectopic pregnancy
- Molar pregnancy
Discuss the use of ultrasound and endocrine assessments in early pregnancy problems
Describe the management of the common problems and complications of early pregnancy, including the conservative, medical and surgical management of:
- Miscarriage (including cervical shock)
- Recurrent miscarriage
- Ectopic pregnancy
- Molar pregnancy
Hyperemesis gravidarum

Clinical competencies

Take a relevant gynaecological history in a woman complaining of vaginal bleeding and/or abdominal pain in early pregnancy
Perform a urinary pregnancy test and interpret the result
Perform a circulatory assessment and abdominal examination of a woman with an early pregnancy problem, and identify those requiring immediate intervention
Initiate appropriate resuscitation of a woman presenting in early pregnancy with cardiovascular collapse
Be able to communicate effectively and sensitively with patients and relatives

Professional skills and attitudes

Consider the need for a supportive environment that addresses religious and cultural issues around early pregnancy loss

Bleeding in early pregnancy

Vaginal bleeding occurs in up to 25% of pregnancies prior to 20 weeks. It is a major cause of anxiety for all women, especially those who have experienced previous pregnancy loss, and may be the presenting symptom of life-threatening conditions such as ectopic pregnancy. Bleeding should always be considered abnormal in pregnancy and investigated appropriately.

A small amount of bleeding may occur as the blastocyst implants in the endometrium 5–7 days after fertilization (implantation bleed). If this occurs at the time of expected menstruation, it may be confused with a period and so affect calculations of gestational age based the last menstrual period.

The common causes for bleeding in early pregnancy are miscarriage, ectopic pregnancy and benign lesions in the lower genital tract. Less commonly it may be the presenting symptom of hydatidiform mole or cervical malignancy.

Miscarriage

The recommended medical term for pregnancy loss under 24 weeks is miscarriage . In some countries, such as the United States, this term is used to describe pregnancy loss before fetal viability or a fetal weight of less than 500 g. In some states in Australia, the term is used for any pregnancy loss under 20 weeks. Most miscarriages occur in the second or third month and occur in 10–20% of clinical pregnancies. It has been suggested that a much higher proportion of pregnancies miscarry at an early stage if the diagnosis is based on the presence of a significant plasma level of beta-subunit human chorionic gonadotrophin (hCG).

The aetiology of miscarriage

In many cases no definite cause can be found for miscarriage. It is important to identify this group, as the prognosis for future pregnancy is generally better than average.

Epidemiological factors

Maternal age and the number of previous miscarriages are independent risk factors for further miscarriage. The risk of miscarriage increases from 11% in women aged 20–24 to more than 50% in women conceiving over the age of 45. This is in part related to the increased risk of chromosome abnormalities (see later) in the conceptus and in part a decline in the number and quality of the woman’s remaining oocytes. The risk of miscarriage is also higher in couples where the man is over the age of 40.

Genetic abnormalities

Chromosomal abnormalities are a common cause of early miscarriage and may result in failure of development of the embryo, with formation of a gestation sac without the development of an embryo or with later expulsion of an abnormal fetus. In any form of miscarriage up to 57% of products of conception will have an abnormal karyotype. The most common chromosomal defects are autosomal trisomies, which account for half the abnormalities, while polyploidy and monosomy X account for a further 20% each. Although chromosome abnormalities are common in sporadic miscarriage, parental chromosomal abnormalities are present in only 2–5% of partners presenting with recurrent pregnancy loss. These are most commonly balance reciprocal or Robertsonian translocations or mosaicisms.

Endocrine factors

Progesterone production is predominately dependent on the corpus luteum for the first 8 weeks of pregnancy, and this function is then assumed by the placenta. Progesterone is essential for the maintenance of a pregnancy, and early failure of the corpus luteum may lead to miscarriage. However, it is difficult to be certain when falling plasma progesterone levels represent a primary cause of miscarriage and when they are the index of a failing pregnancy. The prevalence of polycystic ovarian syndrome (PCOS) is significantly higher in women with recurrent miscarriage than in the general population. Women with poorly controlled diabetes and untreated thyroid disease are at higher risk of miscarriage and fetal malformation.

Maternal illness and infection

Any severe maternal febrile illnesses associated with infections, such as influenza, pyelitis and malaria, predispose to miscarriage. Specific infections such as syphilis, Listeria monocytogenes, mycoplasma and Toxoplasma gondii may also be associated with sporadic miscarriage, but there is no evidence that these organisms cause recurrent miscarriage, particularly in the second trimester. The presence of bacterial vaginosis has been reported as a risk factor for pre-term delivery and second-trimester, but not first-trimester, miscarriage. Other severe illnesses involving the cardiovascular, hepatic and renal systems may also result in miscarriage.

Maternal lifestyle and drug history

Antidepressant use and periconceptual non-steroidal anti-inflammatory drugs have been associated with miscarriage. Smoking, alcohol (more than 5 units a week), caffeine (more than 3 cups per day), cocaine and cannabis have been associated with an increase in the risk of miscarriage, although current evidence is insufficient to confirm a causal link. There is some evidence that obesity may also be associated with pregnancy loss.

Abnormalities of the uterus

The exact contribution that congenital abnormalities of the uterine cavity, such as a bicornuate uterus or subseptate uterus, make to miscarriage remains controversial. The reported incidence of uterine anomalies in women with recurrent miscarriage varies from less than 2% to up to 38%. The impact of the abnormality depends on the nature of the anomaly, and the prevalence appears to be higher in women with second-trimester miscarriage. The fetal survival rate is best where the uterus is septate and worst where the uterus is unicornuate. It must also be remembered that over 20% of all women with congenital uterine anomalies also have renal tract anomalies. Following damage to the endometrium and inner uterine walls, the surfaces may become adherent, thus partly obliterating the uterine cavity (Asherman’s syndrome). The presence of these synechiae may lead to recurrent miscarriage.

Cervical incompetence

Cervical incompetence typically results in second-trimester miscarriage or early pre-term delivery. The miscarriage tends to be rapid, painless and bloodless. The diagnosis is established by the passage of a Hegar 8 dilator without difficulty in the non-pregnant woman or by ultrasound examination or by a premenstrual hysterogram. Cervical incompetence may be congenital and associated with other congenital uterine malformations but most commonly results from physical damage caused by mechanical dilatation or surgery of the cervix or by damage inflicted during childbirth.

Autoimmune factors

Antiphospholipid antibodies – lupus anticoagulant (LA) and anticardiolipin antibodies (aCL) – are present in 15% of women with recurrent miscarriage but only 2% of women with normal reproductive histories. Without treatment, the live birth rate in women with primary antiphospholipid syndrome may be as low as 10%. Pregnancy loss is thought to be due to thrombosis of the uteroplacental vasculature and impaired trophoblast function. In addition to miscarriage there is an increased risk of intrauterine growth restriction, pre-eclampsia and venous thrombosis.

Thrombophilic defects

Defects in the natural inhibitors of coagulation – antithrombin III, protein C and protein S – are more common in women with recurrent miscarriage. The majority of cases of activated protein C deficiency are secondary to a mutation in the factor V (Leiden) gene.

Alloimmune factors

Research into the possibility of an immunological basis of recurrent miscarriage has generally explored the possibility of a failure to mount the normal protective immune response or if the expression of relatively non-immunogenic antigens by the cytotrophoblast may result in rejection of the fetal allograft. There is evidence that unexplained spontaneous miscarriage is associated with couples who share an abnormal number of human leukocyte antigen (HLA) antigens of the A, B, C and DR loci. Treatment with paternal lymphocytes and immunoglobulins has been shown not to be effective and is potentially dangerous.

Clinical types of miscarriage

Threatened miscarriage

The first sign of an impending miscarriage is the development of vaginal bleeding in early pregnancy ( Fig. 18.1 ). The uterus is found to be enlarged, and the cervical os is closed. Lower abdominal pain is either minimal or absent. Most women presenting with a threatened miscarriage will continue with the pregnancy irrespective of the method of management.

Inevitable/incomplete miscarriage

The patient develops abdominal pain usually associated with increasing vaginal bleeding. The cervix opens, and eventually products of conception are passed into the vagina. However, if some of the products of conception are retained, the miscarriage remains incomplete ( Fig. 18.2 ).

Distension of the cervical canal by products of conception can cause hypotension and bradycardia (cervical shock).

Case study: Incomplete miscarriage

A 32-year-old Asian woman presented with a history of 12 weeks amenorrhoea and vaginal bleeding followed by severe lower abdominal pain. On admission to hospital, she was sweating, pale and hypotensive. Her pulse rate was 68 beats/minute. She complained of generalized lower abdominal pain. Initially, a ruptured tubal pregnancy was suspected because of the pain and shock, until vaginal examination revealed copious products of conception protruding from an open cervical os. Removal of these products largely relieved the pain and allowed the uterus to contract, thus reducing the blood loss. Subsequent evacuation of retained products of conception was performed after appropriate resuscitation and preparation.

Complete miscarriage

An incomplete miscarriage may proceed to completion spontaneously, when the pain will cease and vaginal bleeding will subside with involution of the uterus. Spontaneous completion of a miscarriage is more likely in miscarriages over 16 weeks’ gestation than in those between 8 and 16 weeks’ gestation, when retention of placental fragments is common.

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