Block #1
1.1
OUTLINE
Endometrial changes in pregnancy
First Trimester Spontaneous Abortion
Induced Abortions
Surgical Abortion
Midtrimester Abortions
Medical Abortion
St. Luke’s College of Medicine Batch 2018
DR. CATAN, MD, FPOGS
July 29, 2015
Lecture; Audio; Williams Obstetrics, 24th Ed Reference:
Williams Obstetrics 24th Edition
CPG on Abortion published by the Philippine Obstetrical and Gynecological Society
CPG on Gestational Trophoblastic Disease (November 2011) published by the Philippine Society for the Study of Trophoblastic Diseases, Inc.
Objectives:
Enumerate the most important differential diagnoses for first trimester bleeding.
Diagnose abortion, ectopic pregnancy, and Hydatidiform Mole.
Identify risk factors for these.
Know their classic clinical presentations.
Give the principles of management for these first trimester complications of pregnancy.
Fig. 1. Normal 1st Trimester Transvaginal Sonography (TVS)
Fig. 2. Arias-Stella Reaction
Latin: Aboriri- “to miscarry”
It is thus appropriate the following words are used interchangeably:
Ectopic Pregnancy
Dispermic Pregnancy o Hydatidiform Mole
Spontaneous or induced pregnancy termination before
20 weeks gestation or with a fetus born weighing less than 500 g (WHO, CDCP)
Criteria by WHO and Centers for Disease Control and Prevention are contradictory because the mean birth weight of a 20 week fetus is 320 g, whereas 500 g is the mean for 22 to 23 weeks (Moore 1977)
TVS and hCG among other practices are used to identify early pregnancies, intrauterine versus ectopic location, and distinguish a chemical and a clinical pregnancy.
An ad hoc international consensus group proposed the term Pregnancy of Unknown Location (PUL) with the goal of early identification and management of ectopic pregnancy (Barnhart, 2011; Doubilet 2013)
Classification
Spontaneous abortion
threatened
inevitable
incomplete
complete
missed
septic
Recurrent abortion- women with repetitive spontaneous abortions so that an underlying factor(s) can be related to achieve a viable newborn.
Induced abortion- surgical or medical termination of a live fetus that has not reached viability
More than 80% of spontaneous abortion occurs within the first trimester.
Death is usually accompanied by hemorrhage into the decidua basalis.
This is followed by adjacent tissue necrosis.
Tissue necrosis stimulates uterine contractions.
The gestational sac detaches. It is usually filled with fluid and may or may not contain an embryo or fetus.
Anembryonic- 50%; has no identifiable embryonic elements. Less accurately, the term blighted ovum may be used. (no fetus)
Abortion rates and chromosomal anomalies decrease with advancing gestational age.
Occurs at earlier gestational ages
75% occurred by 8 weeks (Kaji et al, 1980). Of these, 95% are caused by maternal gametogenesis errors, and 5% occur by paternal errors (Jacobs, 1980).
With first-trimester miscarriages, autosomal trisomy is the most frequently identified chromosomal anomaly
Most trisomies result from isolated nondisjunction
Trisomies have been identified in arbotuses for all except chromosome number 1; most common with 13,
16, 18, 21, and 22
Monosomy X (45,x) is the single most frequent specific chromosomal abnormality " Turner syndrome " usually results in abortion
Autotomal monosomy is rare and incompatible with life
Triploidy- often associated with hydropic or molar placental degeneration; advanced maternal and paternal age do not increance the incidence
Tetraploid fetus- abort early in gestation; rarely liveborn
Chromosomal structural abnormalities infrequently cause abortion
Abort later than aneuploid, peaks at ~13 weeks (Kajii, 1980).
Incidence of euploid abortions increases dramatically after maternal age exceeds 35 years (Stein, 1980).
MATERNAL FACTORS
Mycoplasma
Ureaplasma
Oakeshott et al reported an association between second trimester miscarriage and bacterial vaginosis.
No arbortifacient effects caused by Listeria monocytogenes, parvovirus, cytomegalovirus, Herpes simplex, Hepatitis B virus, Tuberculosis.
Brucella abortus, Campylobacter fetus, and Toxoplasma gondii cause abortion in livestock.
Rarely due to chronic wasting diseases such as tuberculosis or carcinomatosis.
Unrepaired cyanotic heart disease- increases risk
Inflammatory bowel disease- increase risk
Anorexia nervosa, and bulimia nervosa- linked with subfertility, preterm delivery, and fetal-growth restriction
Recurrent miscarriages- increased risk for fetal-growth restriction, more likely to suffer myocardial infarction
Chronic hypertension- no significant risk
RHD- no risk
Thyrotoxicosis- no risk
Severe iodine deficiency- increased risk
Hypothyroidism- unclear
OCP, spermicidal agents, NSAIDs- no risk
Intrauterine device (IUD) in situ- increase risk
Radiotherapy- increase risk for miscarriages, low-birth weight and growth-restricted infants, preterm delivery, and perinatal mortality except in exposure to <5 rads
Cancer survivors treated with abdominopelvic radiotherapy- increase risk
Chemotherapy- not well defined
Methotrexate- increase risk
Surgery
Uncomplicated surgical procedures- no risk
Ovarian tumor resection- no risk
Uncomplicated surgery for ovarian tumors may be done without causing miscarriage
An important exception involves early removal of
Trauma- seldom causes first-trimester miscarriage; major trauma especially abdominal can cause fetal loss, but is more likely as pregnancy advances.
Daily consumption of fruit and vegetables- decrease risk
Sole deficiency of one nutrient, or moderate deficiency of all- no risk
Hyperemesis gravidarum- rare
Low level consumption of alcohol- no significant risk
Occupational Risks
Chemotherapeutic agents
Sterilizing agents- increase risk
Ultrasound- no risk
MRI- no risk
Video display terminals- no risk
IMMUNOLOGICAL FACTORS
INHERITED THROMBOPHILIAS
American College of Obstetricians and Gynecologists is of the opinion that there is not a definitive causal link between inherited thrombophilias and adverse pregnancy outcomes in general, and abortion in particular.
Other terms: recurrent spontaneous abortion, recurrent pregnancy loss, and habitual abortion
Definition: Three or more consecutive pregnancy losses at < or equal to 20 weeks or with a fetal weight < 500 grams
Uterine leiomyomas especially if located near the placental implantation site can cause miscarriage, but data shows no significant cause of recurrent pregnancy loss (Saravelos, 2011). Uterine cavity distortion is apparently not requisite for bad outcomes (Sunkara, 2010).
Fig. 4. Threatened Abortion- note hemorrhage, no embryo,
irregular sac
Fig. 3. Congenital uterine anomalies
PATERNAL FACTORS
chromosomal abnormalities in sperm- increase risk
increasing paternal age- increase risk; lowest before 25 years and progressively increase at 5-year intervals
Bloody vaginal discharge or bleeding appears through a
closed cervical os (closed cervix) during the first 20 weeks
With miscarriage, bleeding usually begins first, and cramping abdominal pain follows hours to days later
Low-midline clearly rhythmic cramps, persistent low backache with pelvic pressure, or dull and midline suprapubic discomfort may be present
Bleeding is the most predictive risk factor for pregnancy loss (Eddleman, 2006).
Women with early pregnancy, vaginal bleeding, and pain should be evaluated for an ectopic pregnancy.
Threatened abortion versus ectopic pregnancy is differentiated with repeat evaluation of serum B-hCG and progesterone levels and transvaginal sonography.
Uterine pregnancy- increase of 53-66% B-hCG levels every 48 hours
Dying pregnancy- <5 ng/mL serum progesterone
Healthy pregnancy- >20 ng/mL serum progesterone
Transvaginal sonography- locate the pregnancy and determine if the fetus is alive " if cannot be done, then Pregnancy of Unknown Location is diagnosed
Gestational sac- an anechoic fluid collection that represents the exocoelomic cavity; may be seen by 4.5 weeks " B-hCG levels are generally considered to be 1500 to 2000mlU/mL
Pseudogestational sac- seen with ectopic pregnancy, excluded once a yolk sac is seen by 5.5 weeks, with a 10 mm mean gestational-sac diameter
At 5 to 6 weeks, a 1- to 2-mm embryo adjacent to the yolk sac can be seen " absence of an embryo in a sac with a mean sac diameter of 16 to 20mm suggests a deaf fetus
Anembryonic gestation- diagnosed when the mean gestational sac diameter measures � 20 mm, and without an embryo
Embryonic death- diagnosed if an embryo measuring �10 mm has no cardiac activity
Gross rupture of the membranes along with cervical dilatation in the first trimester is followed by uterine contractions or infection. (bag of water is still intact, but is already coming out?)
After 48 hours, if no additional amniotic fluid has escaped, without bleeding, cramping, or fever, patient may resume ambulation and pelvic rest.
If with bleeding, cramping, or fever, abortion is considered inevitable, and the uterus is evacuated.
Products has not yet come out
Bleeding that follows partial or complete placental separation and dilation of the cervical os.
Fetus and placenta may remain within the uterus, or are partially extruded. some of the products of conceptus has already come out
Expelled together before 10 weeks, but later, they deliver separately.
Managed with curettage, medical abortion, or expectant management. May need cervical dilatation before curettage, or extraction of placental tissue with ring forceps.
Fig. 5. Selected views of the lower uterine segment demonstrate a miscarriage in progress. Essentially, a threatened
miscarriage progresses to an inevitable miscarriage if cervical dilatation occurs. Once tissue has passed through the cervical os, this will then be termed an incomplete miscarriage and ultimately a complete miscarriage.
Heavy bleeding, cramping, and passage of tissue or a fetus
Closed cervical os.
Characterized by a minimally thickened endometrium without a gestational sac but recent studies show ectopic pregnancy can also be associated with heavy bleeding, empty uterus, and <15mm endometrium. This is confirmed if there is a sonography of the first intrauterine pregnancy, and then later an empty cavity.
Also termed early pregnancy failure, loss, or wastage
Describes dead products of conception that were retained in the uterus with a closed cervical os.
Early pregnancy appeared to be normal with amenorrhea, nausea and vomiting, breast changes, and uterine growth.
Suspected fetal death could not be confirmed " expectant management was the sole option " spontaneous miscarriage would eventually ensue
Time of fetal death could not be determined clinically
Confirmed with B-hCG assays and TVS, and managed with uterine evacuation
Bacteria gain uterine entry and colonize dead conception products, to cause myometritis, parametritis, peritonitis, septicemia, and rarely endocarditis.
Severe necrotizing infections, and toxic shock syndrome
Etiologic agents: Streptococcus pyogenes, Clostridium perfringens, Clostridium sordellii
Managed with broad-spectrum antibiotics, suction curettage (if there are retained products or fragments), and prophylactic antibiotics like Doxycycline to prevent postabortal sepsis
Fig. 6. Classification of Abortion
Immature chorionic villi in early pregnancy
2 layers of trophoblasts:
o syncytiotrophoblast
o cytotrophoblast
Fig. 8. First trimester chorionic villi composed of a delicate mesh of central stroma surrounded by two discrete layers of epithelium- the outer syncytiotrophoblast (2 arrows) and the inner cytotrophoblast (1 arrow)
Fig 9. Histology of Abortion
Expectant and medical management are associated with unpredictable bleeding.
Expectant; has failure rates as high as 50%
Medical (not yet available in the Phil)
Prostaglandin; has varying failure rates of 5 to 40%
Misoprostol o Mifepristone o Methotrexate o Oxytocin
Curettage usually results in a quick resolution that is 95 to 100% successful.
Defined as the medical or surgical termination of pregnancy before the time of fetal viability.
Definitions to describe frequency: Abortion ratio" the number of abortions per 1000 live births; and Abortion rate" the number of abortions per 1000 women aged 15 to 44 years
Classification
Therapeutic Abortion- indicated if patient has persistent decompensation especially with pulmonary hypertension, advance hypertensive vascular disease or diabetes, and malignancy; commonly to prevent birth of a fetus with significant anatomical, metabolic, or mental deformity
Elective or Voluntary abortion- interruption of pregnancy before viability not for medical reasons
First-trimester abortion techniques aided by pretreatment using cervical dilators
Surgical
Dilatation and curettage
Vacuum aspiration
Menstrual aspiration
Medical
Prostaglandins and analogues
Antiprogesterones- mifepristone and epostane
Methotrexate
Transvaginal through dilated cervix, rarely laparotomy with either hysterotomy or hysterectomy. Following dilatation of the cervix, evacuating the pregnancy is done by mechanically scraping out the contents- sharp curettage, or by suctioning out the contents-suction curettage or both. Both is recommended for gestations < or equal to 15 weeks.
From end of the first trimester until the fetus weighs > or equal to 500 g or gestational age reaches 20 weeks (22 to 23 weeks is more accurate). Risk factors include: first-trimester bleeding, race, ethnicity, prior poor obstetrical outcomes,
extremes of maternal age. Management is similar to first-
trimester abortions, except that oxytocin is highly effective for labor induction or augmentation. Surgical termination by dilation and evacuation has fewer complications than labor induction (Bryan, 2011; Edlow, 2011).
Some of the cause of Midtrimester Spontaneous Pregnancy Losses
Fetal anomalies o Chromosomal o Structural
Abruption, previa
Defective spiral artery transformation
Uterine defects
Characterized classically by painless cervical dilatation in the second trimester" followed by prolapse and ballooning of membranes into the vagina" expulsion of an immature fetus
Risk factors: previous cervical trauma such as dilatation and curettage, conization, cauterization, or amputation
Congenital
Leiomyomas
Maternal disorders
Autoimmune
Infections
Metabolic
Fig. 10. Stages of Cervical Incompetence, characterized by painless cervical dilatation, followed by prolapse and ballooning of membranes into the vagina and expulsion of an immature fetus. Treated surgically with cerclage except if with bleeding, uterine contractions, or ruptured membranes.
Fig. 11. Trust Your Vaginal Ultrasound!
Fig. 12. Treatment for Incompetent Cervix. Cervix is sewn closed to help prevent pregnancy loss or premature birth.
Reinforces a weak cervix by a purse-string suture
Contraindications: bleeding, uterine contractions, or ruptured membrane
Principal complications: membrane rupture, preterm labor, hemorrhage, infection
MEDICAL ABORTIONS
Alternative to surgical pregnancy termination in women less than 49 days’ menstrual age (surgical abortion is preferred after this time)
Only 3 medications for early medical abortion have been widely studied:
Antiprogestin Mifepristone- increases uterine contractility by reversing progesterone-induced inhibition.
Antimetabolite Methotrexate- same as mifepristone
Prostaglandin Misoprostol- directly stimulates the myometrium; given initially, alone or with methotrexate or mifepristone
Case 1: 40 year old, G1 P0, positive pregnancy test, bleeding at 9 weeks, no uterine contents
Threatened Abortion
Inevitable Abortion
Incomplete Abortion
Case 1: 40 year old, G1 P0, positive pregnancy test, bleeding at 9 weeks, no uterine contents
A. Incompetent cervix
Diabetes Mellitus
Antiphospholipid antibody syndrome
Table. Adverse Outcomes That are increased in Women with Threatened Abortion
