The First Trimester: Conception, Bleeding, pregnancy loss, ectopic pregnancy ppt

Conception and Early Development

• Follicular Phase: Meiosis in ovaries begins in utero, arrested in Prophase of Meiosis I until the LH surge triggers completion of Meiosis I and the start of Meiosis II.
• Fertilization Process: Sperm DNA makes contact with the secondary oocyte in the tubal ampulla; only about 200 out of 200-500 million sperm reach the oocyte.
• Acrosome Reaction: Sperm must penetrate layers surrounding the oocyte using digestive enzymes from the acrosome to fuse with the egg's plasma membrane.
• Zygote Formation: After fusion, the pronuclei of sperm and egg combine, forming a zygote with a complete set of chromosomes.

Implantation and Placenta Development

• Embryo Journey: Cell divisions occur every 12-24 hours, reaching the uterus at the blastocyst stage on approximately day 6, with implantation around days 7-9.
• Trophoblast Function: The outer sphere of cells becomes the placenta and fetal membranes, penetrating the endometrium and forming placental villi for maternal blood supply.
• Placental Growth: By delivery, the placenta can weigh up to one pound and comprises millions of capillaries.

First Trimester Bleeding

• Bleeding Incidence: First trimester bleeding occurs in 20-25% of pregnancies, with 50-75% of those pregnancies continuing despite bleeding.
• Risk Factors for Loss: Heavy bleeding, cramping, or pain increases the risk of pregnancy loss; detection of fetal cardiac activity and rising β-hCG decreases this risk substantially.

Types of Abortion

• Abortion Definitions:
  • Spontaneous Abortion (SAB): Premature end to pregnancy before 20 weeks.
  • Elective Abortion: Voluntary termination of pregnancy.
  • Threatened Abortion: Bleeding during an intrauterine pregnancy.
  • Inevitable Abortion: Open cervical os with ongoing bleeding.
  • Incomplete Abortion: Retained uterine contents despite cervical dilation.
  • Anembryonic Gestation: Gestational sac present without fetal development.

Common Causes of First Trimester Bleeding

• Differential Diagnoses:
  • Normal intrauterine pregnancy.
  • Abnormal intrauterine pregnancy.
  • Ectopic pregnancy.
  • Other benign causes, such as implantation bleeding or cervical irritation.

Diagnostic Tools

• HCG Testing:
  • Urine tests (UHCG/UPT) and serum β-hCG tests are crucial for early pregnancy diagnosis.
  • Normal β-hCG levels double every 48 hours in a healthy pregnancy.
  • The discriminatory zone for ultrasound visualization is 1000-2000 IU/L for vaginal and 5000-6000 IU/L for abdominal ultrasound.
• Transvaginal Ultrasound: More sensitive than abdominal ultrasound for early pregnancy assessment.

Management of First Trimester Bleeding

• Initial Steps: Check serum β-hCG levels and perform vaginal ultrasound if positive.
• Possible Outcomes:
  • Visualization of an intrauterine pregnancy significantly lowers the risk of ectopic or non-viable pregnancy.
  • If no intrauterine gestation is seen, consider ectopic pregnancy until proven otherwise.
• Patient Monitoring: Serial β-hCG and ultrasounds should guide management, with the involvement of an OBGYN.

Blood Type Considerations

• Rh Factor Prevention: Always order blood type and Rh factor for bleeding patients; administer Rhogam if the patient is Rh-negative to prevent Rh sensitivity in future pregnancies.

Management of Nonviable First Trimester IUP

• Uterine Evacuation Methods:
  • Suction (Manual or Electric) for evacuation.
  • Medications can assist in uterine evacuation.
  • Conservative management allows for spontaneous completion of many spontaneous abortions (SABs).

Medical Management of Nonviable IUP

• Misoprostol:

  • Synthetic prostaglandin E1 analogue.
  • Cost-effective and can be administered orally or vaginally.
  • Promotes uterine contractions and cervical ripening.

• Mifepristone + Misoprostol:

  • Begins with Mifepristone orally, followed by Misoprostol vaginally 24-48 hours later.
  • Highly effective with minimal side effects.

• Comparison:

  • Mife/Miso combination is more effective than Misoprostol alone.
  • Legal status of Mife/Miso may vary by location.

Ectopic Pregnancy

• Definition & Risks:

  • Ectopic pregnancy is a non-intrauterine gestation and is always a life-threatening condition.
  • Most common locations for ectopic pregnancies are the fallopian tubes (95% incidence).
  • Increasing rates associated with ART, infertility treatments, and STDs.

• Risk Factors:

  • Includes traumatic injury, inflammation, endometriosis, smoking, IUD presence, and previous ectopic pregnancies.

Symptoms of Ectopic Pregnancy

• Classic Triad:

  • Includes abdominal pain, amenorrhea, and vaginal bleeding.
  • Only around 50% of ectopic pregnancies present with all three symptoms.

• Vaginal Bleeding Explanation:

  • Occurs due to progesterone effects, leading to uterine lining shedding.

Clinical Examination & Diagnosis

• Rule of Thumb:

  • Always consider ectopic pregnancy in women of childbearing age with abdominal pain and/or vaginal bleeding.

• Clinical Findings:

  • Unilateral lower abdominal pain on examination.
  • Cervical motion tenderness and unilateral adnexal tenderness indicated on vaginal examination.

• Diagnostic Challenges:

  • Patients may misinterpret post-conceptual bleeding as a menstrual period.
  • Heterotopic pregnancies may complicate diagnosis.

Ultrasound and Ectopic Pregnancy

• Discriminatory Zone:
  • BhCG levels of 1,500-2,000 are critical for visualizing a pregnancy via transvaginal ultrasound.
  • Absence of visualization raises suspicion for ectopic pregnancy.

Ruptured Ectopic Pregnancy

• Signs of Rupture:

  • Characterized by sudden, intense pain, abdominal guarding, and potentially shoulder pain from referred blood.
  • Associated with hemodynamic shock or fainting.

• Indicators for Surgical Emergency:

  • Free fluid on point-of-care ultrasound (POCUS).
  • Increased risk if ectopic size exceeds 4cm or BhCG levels exceed 5,000.

Treatment Options for Ectopic Pregnancy

• Surgical Treatments:

  • Laparoscopy is preferred, with laparotomy as an alternative for complex cases.

• Medical Management:

  • Methotrexate administered at 50 mg/kg IM, with possible retreatment if BhCG levels do not decrease appropriately.

• Patient Candidacy:

  • Not all patients qualify for medical management; careful evaluation required.

• Rhogam Consideration:

  • Important to administer Rh immunoglobulin to Rh-negative patients to prevent sensitization when carrying an Rh-positive fetus.