Intro to OB Terminology, OB History, Review of Menstrual, Ovarian & Endometrial Cycles

Lisa Smithers, MSN, APRN, CNM

OB Terminology

• OB: Obstetrics – health care of a woman during pregnancy, childbirth, and postpartum
• GYN: Gynecology – referring to woman/female
• Gestation: Length of time from the first day of the last menstrual period (LMP) to delivery
• Antepartum: term for pregnancy (while woman is pregnant)
• Intrapartum: term for labor and birth; while the woman is in birth (true labor)
• Postpartum: refers to the 6 week period of time after childbirth when a woman’s body is returning to its nonpregnant state
• Neonate: refers to a newborn baby during the first 28 days of life
• Infant: refers to a baby from 1 month to 1 year of life

OB History

• Gravida: the number of pregancies a woman has had, regardless of outcome, including the current pregnancy
  • NOTE: does not mean they have to be currently pregant

Nulligravida – no preganncies, not now

Primigravida – one pregnacies, first pregnacies (can be past or current first pregancy 🡪 think only one child)

Multigravida – has had multiple pregnacies (mischarage or born)

• Para: the number of pregnancies delivered after 20 wks gestation, regardless of whether the baby survives (stillborn or alive & regardless delivery method = C-section or vaginal)
  • Note: 20 WEEK = primipara, vaginal/C-section/abortion (if before = nulli)
  • Key word: deliver

Nullipara – 0 deliveres

Primipara – 1 delivery “primip” (not concidered primi until delivery)

Multipara – 2+ delivers “multip”

OB History (Pregnancy History)

Note : TPA = number of pregancies, not children

G = number of children

• Short History: Gravida and Para (G&P)
• Complete History: Gravida Term Preterm Abortion Living

G (Gravida): Number of pregnancies including current pregnancy

T (Term): Pregnancy delivered between 37 & 42 wks gestation

🡪 number of pregancies, not children number

P (Preterm): Pregnancy delivered between 20 & 36 wks & 6 days gestation

A (Abortions): Pregnancy delivered between conception & 19 wks & 6 days gestation

SAB – spontaneous abortion (miscarriage)

EAB/TAB – elective abortion or “therapeutic” abortion (choice)

L (Living): number of living chlidren, delivered (not pregancies)

Example:

Patient is now 28 wks gestation. She delivered twins at 35 wks gestation who are now 3 years old. She delivered a singleton at 38 wks gestation who is now in kindergarten, and she miscarried at 10 wks gestation one year ago.

Gravida: 4

Para: 2 (10 week gestation = no 🡪 Note: must be 20+ weeks to count)

G4 T1 PreT1 A1 (SAB) L3

Example:

Client had 2 elective abortion (at 8 and 13 wks) prior to delivering a baby at 40 wks gestation followed by a baby at 39 wks gestation 2 years later. She is now pregnant at 16 wks gestation.

Gravida: 5

Para: 2

G5 T2 PreT0 A2 (EAB) L2

Menstrual Cycle

Definition: Menstruation is periodic uterin bleeding that begins approximately 14 days after ovulation.

Key word: 14 days (time ovulation 🡪 period starts)

Hard to predict time of ovulation, end of peiod is not predictable = easy to get unintentinally pregant)

Avg length of entire menstrual cycle: 28 days (range 25-32 days)

First day of menstrual bleeding is designated as day one (LMP) of cycle.

Avg duration of flow is 5 (range 2-8 days).

Avg blood loss is 40 ml (range 20-80 ml). 5ml = 1 tsp 15ml = 1tbs 30 = 2 tbs (loose 2tbs & 2tsp)

Feedback Loop

Note: in response to hormones

• During menstruation, the CNS sends a message to the hypothalamus that estrogen & progesterone levels are low. Day 1 of menstruation starts the _____________ ___________ of the menstrual cycle.
• The hypothalamus responds by sending Gonadotropin Releasing hormone to the Anterior Pituitary.
• The anterior pituitary responds by sending Folical stimulating hormone (FSH) and then Luteinizing Hormone (LH) to the ovary.
• The ovary responds to FSH by selecting a follicle for maturation. The chosen follicle that begins to mature is called the Graafian follicle.
• LH stimulates the follicle to release the ovum and ovulation occurs, starting the luteal phase (static/ follicular phase is variable) of the menstrual cycle. The Graafian follicle becomes a corpus luteum which produces both estrogen & prodesterone until the placenta is established to do so.

Conception occurs: levels decrease, cycle repeats

• High levels of estrogen and prodesterone are present.

If conception does not occur, levels of both gradually decrease as the corpus luteum

disintegrates. When estrogen levels are low again, cycle begins

and the cycle repeats.

If conception occurs: Levels of estrogen & prodesterone

continue to rise.

CNS sends message to hypothalamus that estrogen levels are high.

So… Hypothalamus stops sending Gonadotropin Releasing Hormone to the

Anterior Pituitary.

So… The Anterior Pituitary stops sending FSH and LH to the ovaries.

Resulting in no follicle being selected for ripening and menstrual cycle stops.

High levels of estrogen & prodesterone

throughout pregnancy prevent menstruation from occurring.

OVARIAN CYCLE (2 Phases)

1. Pre-ovulatory: Follicular Phase - First 14 days of menstrual cycle if 28-day cycle
2. Estrogen is the dominant hormone.
3. Luteinizing Hormone peaks 10-12 hrs before ovulation.
4. Ovulation occurs on day 14 if a 28-day cycle, or 14 days before the next menstruation

Mittelschmerz: mid-cycle pain associated w/ ovulation

1. Post-ovulatory: Luteal Phase – period of time after ovulation before menstruation (last 14 days)

NOTE: EXAM!!! KNOW LUTEAL IS STATIC/FOLLICULAR PHASE IS VARIABLE!!!

1. Prodesterone is the dominant hormone.

ENDOMETRIAL CYCLE (4 Phases)

Note: not pregant = only phase 1-3

1. Menstrual Phase (Days 1-5)

Blood flow from shedding endometrium

1. Proliferative Phase (Days 6-14)

Endometrium proliferates (w/ increased vascularization)

1. Secretory Phase (Days 15-25, only in a 28 day cycle)

Uterus prepares to receive fertilized ovum

Corpus Luteum secretes estrogen & prodesterone

1. Escemic Phase (Days 26-28)

This phase occurs only if fertilization does not occur

Vasospasm of endometrial blood vessels causes ischemia/necrosis of endometrium (ischemia causes pain)

Areas of necrosis separate from basal layers, r/i menstration

Corpus luteum regresses r/i decreased estrogen and progesterone

FACTS to KNOW

• PREGNANCY: Primary hormone which maintains pregnancy: prodesterone
• MENARCHE: Onset of first menstruation in a womans life

Usually occurs around age 12 ½ or within 2 yrs breast development

For 1+ years, cycles are irregular, unpredictable, painless & anovulatory

• MENOPAUSE: Menstruation has ceased for at least one year

Usually occurs around age 51 (or 51½)

• PERIMENOPAUSE: The period of time just before and after menopause when hormone transitions are occurring

Conception:

Gametogenesis:

Gamete:

Sperm: male gamete

Ovum (Ova): egg

Male Spermatogensis:

When: puberty

Where:

1) mitosis