Early Pregnancy

Published on 10/03/2015 by admin

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Last modified 10/03/2015

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Chapter 15 Early Pregnancy

Miscarriage 308

Threatened Miscarriage 308
Inevitable Miscarriage 308
Complete Miscarriage 308
Incomplete Miscarriage 309
Missed Miscarriage 309
Other Terms 309
Management 310

Early Pregnancy Loss (≤12 Weeks’ Gestation) 310
Late Pregnancy Loss (>12 Weeks’ Gestation) 313
Recurrent Miscarriage 314

Introduction and Definitions 314
Causes of Recurrent Miscarriage 314
Investigation and Treatment of Recurrent Miscarriage 316
Termination of Pregnancy 317

First Trimester Termination of Pregnancy 317
Second Trimester Termination of Pregnancy 319
Complications of Termination of Pregnancy 319
Ectopic Pregnancy 320

Aetiology 320
Diagnosis of Tubal Pregnancy 321

Symptoms 321
Signs 321
Diagnosis of Tubal Pregnancy 321
Sites of Implantation 323

Rupture of the Tube 323
Rupture into Lumen of Tube 323
Treatment of Tubal Pregnancy 324

Methotrexate 324
Salpingectomy 324
Salpingostomy 324
Conservative 324
Gestational Trophoblastic Disease 325

Pathology 326
Presentation and Genetics 327
Treatment 328
Gestational Trophoblastic Neoplasia 328
Chemotherapy for Choriocarcinoma 330

Miscarriage

Miscarriage occurs in 10–20% of clinical pregnancies, and in the UK it is defined as a pregnancy loss before the 24th week of gestation. In Australia, miscarriage is a pregnancy that spontaneously ends before 20 weeks. After the 20th week of pregnancy, the loss of a fetus is called a stillbirth.

Threatened miscarriage

Technically this refers only to bleeding from the placental site, which is not yet severe enough to terminate the pregnancy. Usually the bleeding is slight and the cervix remains closed. The pregnancy is likely to remain viable.

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Inevitable miscarriage

Clinically, the amount of bleeding is variable but the cervix is open. On ultrasound examination, the bleeding is retroplacental and often, fetal heart activity is absent.

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Complete miscarriage

A miscarriage in which the fetus, membranes and chorionic tissue are completely expelled from the uterus is termed a complete miscarriage.

Incomplete miscarriage

A miscarriage in which the fetus or membranes or chorionic tissue are incompletely expelled from the uterus. An ultrasound will show debris (retained products of conception) within the uterine cavity.

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Missed miscarriage

It is defined as the retention of a non-viable fetus for several weeks without any clinical symptoms.

Other terms

The term early fetal demise is now used to describe what used to be known as an anembryonic pregnancy or a blighted ovum and denotes pregnancies in which a gestational sac is present without the development of a fetal pole.

Management

The method of management of miscarriage depends upon the gestation of miscarriage and clinical facilities available. Apart from expectant management, these methods are identical to those performed during an elective termination of pregnancy.

Early pregnancy loss (≤12Weeks’ Gestation)

Surgical

Clinical indications for surgical evacuation include: persistent excessive bleeding, haemodynamic instability, evidence of infected retained tissue, suspected gestational trophoblastic disease and patient choice. Surgical uterine evacuation for a miscarriage should be performed using a suction curettage. Where infection is suspected, delaying surgical intervention for 12 h is recommended to allow intravenous antibiotic administration.

Preoperative cervical preparation essentially softens the cervix making it easier to dilate and, in doing so, minimises force of dilatation required, haemorrhage and uterine/cervical trauma. The cervix can be prepared using:

– gemeprost (prostaglandin E1) given as a vaginal pessary 3 h before surgery
– misoprostol (a prostaglandin analogue) given vaginally 3 h before surgery
– mifepristone (an antiprogesterone) given orally at least 12 h before surgery
– laminaria tents inserted into the external cervical os.

Surgical Evacuation of the Products of Conception

Curettage

The patient is anaesthetised and the cervix is dilated. Once dilatation is sufficient, vacuum aspiration of the uterine contents is carried out.

A plastic suction curette is commonly used and is less likely to damage the uterus than metal instruments. Plastic curettes are available in diameters from 4 to 12 mm. The cervix is conventionally dilated to a diameter that is 2 mm less than the gestation age in weeks.

Complications

1. Incomplete uterine evacuation.

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2. Uterine perforation and/or damage to abdominal viscera.
3. Sepsis. Broad spectrum antibiotics have been shown to minimise the risk of post-abortal infection.
4. Haemorrhage. Blood loss can be minimised by the use of prostaglandins for preoperative cervical ripening. Bleeding during or after the procedure can be reduced by oxytocic agents such as ergometrine or Syntocinon.
5. Rhesus isoimmunisation. Anti-D should be administered to all rhesus negative women.

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Further tissue can be removed with a sponge forcep or a curette. The concave side of the curette loop is pressed against the uterine wall and pulled down. A ‘clean’ uterine wall gives a characteristic sensation to the operating hand.

Reported serious complications of surgery include perforation of the uterus, cervical tears, intra-abdominal trauma, intrauterine adhesions and haemorrhage.

Medical

Medical methods are an effective alternative in the management of a confirmed first-trimester miscarriage. Various medical methods have been described which use prostaglandin analogues (gemeprost or misoprostol) with or without antiprogesterone priming (mifepristone). Protocols should be developed locally with appropriate selection criteria, therapeutic regimens and arrangements for follow-up. To avoid unnecessary anxiety, women should be informed that bleeding may continue for up to 3 weeks after medical uterine evacuation.

Expectant

Expectant management is a method that can be offered in cases of confirmed first trimester miscarriage. Patient counselling is particularly important for those women with an intact sac who wish to adopt an expectant approach. They should be aware that complete resolution may take several weeks. Expectant management for incomplete miscarriage is highly effective. Occasionally, the passage of tissue may be associated with heavy bleeding.

Medical and expectant management should only be offered in units where women have access to 24-h telephone advice and emergency admission, if required.

Anti-D Immunoglobulin

Non-sensitised rhesus (Rh) negative women should receive anti-D immunoglobulin in the following situations: ectopic pregnancy, all miscarriages over 12 weeks of gestation (including threatened) and all miscarriages where the uterus has been evacuated (whether medially or surgically).

Anti-D immunoglobulin is not required threatened miscarriages under 12 weeks of gestation unless the bleeding is heavy or is associated with significant pain. It is not required in cases of complete miscarriage under 12 weeks’ gestation and when there has been no formal intervention to evacuate the uterus.

Late pregnancy loss (>12Weeks’ Gestation)

Surgical

Surgical uterine evacuation remains an option for some women. Dilatation and suction curettage is commonly performed up to 14 weeks’ gestation. Beyond this point, dilatation and evacuation (D & E) can be carried out which involves cervical dilatation to a maximum diameter and the removal of intrauterine contents, usually following a destructive procedure. This procedure is not commonly performed in the UK.

Medical

Again, medical methods are effective in the management of a second trimester miscarriage. As in the case of first trimester loss, there are various medical regimens that have been described using prostaglandin analogues (gemeprost or misoprostol) with or without antiprogesterone priming (mifepristone). Again, local protocols should be developed appropriately with selection criteria, therapeutic regimens and arrangements for follow-up.

In cases where antiprogesterones and vaginal prostaglandins are not available, PGE2 can be very slowly instilled into the cervix through a Foley catheter to facilitate cervical ripening.

Recurrent miscarriage

Introduction and definitions

Recurrent miscarriage, defined as the loss of three or more pregnancies, is a distressing problem that affects up to 1% of women. Recurrent miscarriage is a heterogeneous condition that has many possible causes; more than one contributory factor may underlie the recurrent pregnancy losses.

Causes of recurrent miscarriage

Maternal Age

This is an independent risk factor. Advanced maternal age adversely affects ovarian function, giving rise to a decline in the number of good quality oocytes and resulting in chromosomally abnormal conceptions that rarely develop further.

Previous Number of Miscarriages

This is an independent risk factor in so far as the more miscarriages an individual has had, the more likely she is to have another one.

Genetic Factors

In approximately 3–5% of couples with recurrent miscarriage, one of the partners carries a balanced structural chromosomal anomaly. These are most commonly balanced reciprocal or Robertsonian translocations.

Abnormalities in the Embryo

Recurrent pregnancy loss may be owing to an abnormal embryo which is incompatible with life. As the number of miscarriages increases, the presence of a chromosomal abnormality decreases and the chance of a recurring maternal cause increases.

Uterine Abnormalities

It is difficult to assess the exact contribution that congenital uterine anomalies make to recurrent miscarriage. The estimates of the number of women with recurrent miscarriage, who also have uterine abnormalities, range from 2% to 37%. Women who have serious anatomical abnormalities and have not had treatment for them seem to be more likely to miscarry or give birth early. Minor variations in the structure of the womb generally do not cause miscarriage

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Cervical Weakness

The diagnosis of cervical weakness (previously known as incompetence) is usually based on a history of late miscarriage, preceded by spontaneous rupture of membranes or a painless cervical dilatation. This is often over diagnosed as there is currently no satisfactory, objective test that can identify women with cervical weakness in the non-pregnant state.

Endocrine Factors

Maternal diabetes and thyroid disease

Systemic endocrine disorders have been associated with miscarriage. However, they do not cause recurrent miscarriages as long as they are treated and well controlled.

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