Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig CONCEPTION AND BIOPHYSICAL CHANGES

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig OOGENESIS Ovary gives rise to oogonial cells First meiotic division – two unequal cells Second meiotic division – begins at ovulation Three polar bodies One ovum

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FIGURE 11-3-A GAMETOGENESIS INVOLVES MEIOSIS WITHIN THE OVARY AND TESTIS. DURING MEIOSIS, EACH OOGONIUM PRODUCES A SINGLE HAPLOID OVUM ONCE SOME CYTOPLASM MOVES INTO THE POLAR BODIES.

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig SPERMATOGENESIS Production of sperm begins during puberty First meiotic division  Primary spermatocyte replicates and divides Second meiotic division  Secondary spermatocytes replicate and divide Produce four spermatids Series of changes

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FIGURE 11-3-B GAMETOGENESIS INVOLVES MEIOSIS WITHIN THE OVARY AND TESTIS. EACH SPERMATOGONIUM, IN CONTRAST, PRODUCES FOUR HAPLOID SPERMATOZOA.

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig THE PROCESS OF FERTILIZATION Sperm and ovum unite to form a zygote Ova are fertile for 12 to 24 hours Sperm are fertile for 72 hours Takes place in the ampulla of fallopian tube

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig CONCEPTION Necessary functional components a.uterus b.fallopian tubes c.ovaries (eggs) d.hormones e.sperm

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig PREPARATION FOR FERTILIZATION Estrogen levels increase peristalsis in fallopian tubes Fertilization usually takes place in ampulla Single ejaculation – 200 to 500 million spermatozoa Prostaglandins in semen help transport sperm

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig CHANGES IN SPERM Capacitation  Removal of plasma membrane and glycoprotein coat  Loss of seminal plasma proteins Acrosomal reaction  Release of enzymes  Allows entry through corona radiata

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig AFTER SPERM ENTRY Additional sperm blocked by zone pellucida Secondary oocyte completes second meiotic division, forms nucleus of ovum Nuclei of ovum and sperm unite Nuclear membranes disappear Chromosomes pair up Sex of zygote determined

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FERTILIZATION & IMPLANTATION

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FERTILIZATION & IMPLANTATION Several Days Pass Until Bilaminar Blastocyst Implants (6 days) b.double layer development 1)blastocyst - inner layer - solid 2)trophoblast - outer layer - foraging layer (feeding layer) c.implantation d.trophoblast to chorion

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FIGURE 11-4 A. SPERM PENETRATION OF AN OVUM. THE SEQUENTIAL STEPS OF OOCYTE PENETRATION BY A SPERM ARE DEPICTED MOVING FROM TOP TO BOTTOM.

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FIGURE 11-4 B. SPERM PENETRATION OF AN OVUM. SCANNING ELECTRON MICROGRAPH OF HUMAN SPERM SURROUNDING A HUMAN OOCYTE (750 ). THE SMALLER SPHERICAL CELLS ARE GRANULOSA CELLS OF THE CORONA RADIATA. SOURCE: USED WITH PERMISSION FROM NILSSON, L. (1990). A CHILD IS BORN. NEW YORK, NY: DELL PUBLISHING.

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig PREEMBRYONIC STAGE First 14 days of human development Cleavage Blastomeres form morula Blastocyst  Develops into embryonic disc and amnion Trophoblast  Develops into chorion

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig IMPLANTATION Occurs 7 to 10 days after fertilization Blastocyst burrows into endometrium Endometrium is now called decidua

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig CELLULAR DIFFERENTIATION Primary germ layers  Ectoderm  Mesoderm  Endoderm All tissues develop from primary germ cell layers

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig TABLE 11-2 DERIVATION OF BODY STRUCTURES FROM PRIMARY CELL LAYERS

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig CELLULAR DIFFERENTIATION (CONT’D) Embryonic membranes begin to form  Chorion(outerm membrane contribues to placental development)  Amnion (inner most membranous sac) Amniotic fluid  Functions –protects against physical force, maintains temperature, allows fetal movement  Characteristics-clear, slightly yellow, cc by 3rd trimester,  Abnormal variations- Yolk sac-provides early nourshment

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig CELLULAR DIFFERENTIATION (CONT’D) Umbilical cord  Body stalk fuses with embryonic portion of placenta  Provides circulatory pathway from chorionic villi to embryo  One vein, two arteries  Wharton’s jelly Delivers oxygenated blood to fetus  Two arteries

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig PLACENTA Metabolic and nutrient exchange Maternal portion  Decidua basalis and circulation Fetal portion  Covered by amnion (chorionic villi) Fetal surface covered by amnion

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig PLACENTAL DEVELOPMENT Chorionic villi form spaces in decidua basalis Spaces fill with maternal blood Chorionic villi (provide blood supply to the embryo) Syncytium: outer layer  Cytotrophoblast: inner layer Anchoring villi form septa

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FIGURE LONGITUDINAL SECTION OF PLACENTAL VILLUS. SPACES FORMED IN THE MATERNAL DECIDUA ARE FILLED WITH MATERNAL BLOOD; CHORIONIC VILLI PROLIFERATE INTO THESE MATERNAL BLOOD-FILLED SPACES AND DIFFERENTIATE INTO A SYNCYTIUM LAYER AND A CYTOTROPHOBLAST LAYER.

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig PLACENTAL CIRCULATION After implantation cells differentiate Trophoblast invades endometrium  Opens uterine capillaries Completion of maternal-placental- fetal circulation  About 17 days after conception

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FIGURE VASCULAR ARRANGEMENT OF THE PLACENTA. ARROWS INDICATE THE DIRECTION OF BLOOD FLOW. MATERNAL BLOOD FLOWS THROUGH THE UTERINE ARTERIES TO THE INTERVILLOUS SPACES OF THE PLACENTA AND RETURNS THROUGH THE UTERINE VEINS TO MATERNAL CIRCULATION. FETAL BLOOD FLOWS THROUGH THE UMBILICAL ARTERIES INTO THE VILLOUS CAPILLARIES OF THE PLACENTA AND RETURNS THROUGH THE UMBILICAL VEIN TO THE FETAL CIRCULATION.

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig PLACENTAL FACTS Size of 8-inch dinner plate Consists of cotyledons, chorionic villi branch out from it Structure is complete at the end of 12 th week gestation Grows till 20 th week gestation, covers ½ of uterine surface

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig PLACENTAL FUNCTIONS  Transfers nutrients  Diffuses oxygen and carbon dioxide functioning as fetal lungs  Production of 4hormones  hCG  Progesterone  Estrogens  hCS/hPL  Facilitates transfer of metabolic wastes from the fetus to the maternal ciruclation  Transfers heat from mother to fetus.

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig DEVELOPMENT OF THE FETAL CIRCULATORY SYSTEM Maintains blood flow to placenta Provides fetus with oxygen and nutrients Removes carbon dioxide and waste products Blood flows through umbilical vein into abdominal wall of fetus

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FIGURE FETAL CIRCULATION. BLOOD LEAVES THE PLACENTA AND ENTERS THE FETUS THROUGH THE UMBILICAL VEIN. AFTER CIRCULATING THROUGH THE FETUS, THE BLOOD RETURNS TO THE PLACENTA THROUGH THE UMBILICAL ARTERIES. THE DUCTUS VENOSUS, THE FORAMEN OVALE, AND THE DUCTUS ARTERIOSUS ALLOW THE BLOOD TO BYPASS THE FETAL LIVER AND LUNGS.

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig EMBRYONIC AND FETAL DEVELOPMENT Pregnancy averages 10 lunar months Beginning of last normal menstrual period to birth Most born within 10 to 14 days of calculated date of birth

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig EMBRYONIC STAGE Day 15 to Week 8  Tissues differentiate into essential organs Week 3  Most advanced organ is heart, beginning to beat; well-arked midbrain flexure

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig EMBRYONIC STAGE (CONT’D) Week 4  Beginning development of GI tract  Somites develop – beginning vertebrae  Heart develops, begins beating, circulating blood  Eyes, nose begin to form  Arm, leg buds present

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig EMBRYONIC STAGE (CONT’D) Week 5-8  Trachea developed  Liver produces blood cells  Trunk straighter  Digits develop  Tail begins to recede  1 st indication of ossification  Definitive muscles well represented

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FETAL STAGE Week 9 to birth At 9-11 weeks  Every organ system, structure present  Gestation time  Refining structures-nails appearing, skin pink  Perfecting function

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FETAL DEVELOPMENT: WEEK 12 3 RD LM Eyelids closed Tooth buds appear Fetal heart tones can be heard Genitals well differentiated Urine produced Spontaneous movement occurs

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FETAL DEVELOPMENT: WEEK 16 4 TH LM Head still dominant Lanugo begins to develop Blood vessels clearly developed Active movements present Fetus makes sucking motions Fetus swallows amniotic fluid Fetus produces meconium

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FETAL DEVELOPMENT: WEEK 20 5 TH LM Subcutaneous brown fat appears Quickening felt by mother Nipples appear over mammary glands Fetal heartbeat heard by fetoscope Brain grossly formed Nose and ears ossifying

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FETAL DEVELOPMENT: WEEK 24 6 TH LM Eyes structurally complete Vernix caseosa covers skin Alveoli beginning to form Ability to hear

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FETAL DEVELOPMENT: WEEK 28 7 TH LM Testes begin to descend Lungs structurally mature Minimum tones Fleeting movements Lecithin forming on alveolar surfaces

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FETAL DEVELOPMENT: WEEK 32 8 TH LM Rhythmic breathing movements Ability to partially control temperature Bones fully developed but soft and flexible L/S ratio 2:1 Sense of taste present

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FETAL DEVELOPMENT: WEEK 36 9 TH LM Increase in subcutaneous fat Lanugo begins to disappear L/S ratio >2:1 Definite sleep-wake cycles Skin pink becoming rounded

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FETAL DEVELOPMENT: WEEK TH LM Skin appears polished Lanugo disappears except in upper arms and shoulders Hair now coarse and approximately 1-inch long Fetus is flexed Strong suck reflex

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig TABLE 11-4 EMBRYONIC AND FETAL DEVELOPMENT: WHAT PARENTS WANT TO KNOW

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig FACTORS INFLUENCING DEVELOPMENT Quality of sperm or ovum Genetic code Adequacy of intrauterine environment Teratogens (any agent that interfere with a developing embryo) Organs formed primarily during embryonic development

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig SIGNS AND SYMPTOMS OF PREGNANCY—THIS IS IMPORTANT TO KNOW Presumptive signs of pregnancy (subjective) menstrual suppression (amenorrhea, menstruation may occur after conception) nausea, vomiting, and "morning sickness" (due to increased HCG levels) frequency of micturition (uterus stretches base of bladder) tenderness and fullness of the breasts, breast pigmentation, and discharge (due to increased progesterone, estrogen) "quickening" (usually wks. may be 16 wks. in multigravida) fatigue

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig PROBABLE SIGNS (OBJECTIVE) Dark blue discoloration of the vaginal mucous membrane known as CHADWICK'S SIgn pigmentation of the skin and abdominal striae (may also occur in breasts, buttocks, and thighs) changes in the size, shape, and consistency of the uterus - HEGAR'S SIGN (lower part of the body of uterus much softer than cervix) fetal outline, distinguished by abdominal palpation and detection of a fetal part vaginally by BALLOTTEMENT (sudden tap on presenting part makes it rise in amniotic fluid) changes in the cervix (GOODELL'S SIGN - cervix softens due to increased vascularity edema) BRAXTON HICKS contractions (painless, cause of false labor) positive pregnancy test (increased Hcg levels, blood/serum 8-9 days after ovulation and fertilization and urine test within 2 wks of gestation)

Olds’ Maternal-Newborn Nursing & Women’s Health Across the Lifespan, Ninth Edition Michele Davidson Marcia London Patricia Ladewig POSITIVE SIGNS (DIAGNOSTIC) fetal heart sounds (audible with Doppler 8-10 weeks gestation, or ultrasound) fetal movements felt by examiner x-ray- outline of fetal skeleton ultrasonic demonstration of the presence of a conceptus (6-8 wks. yields most information) fetal movements visible