presumptive (subjective signs) Amenorrhea, nausea, vomiting, increased urinary
frequency, excessive fatigue, breast tenderness, quickening at 18–20 weeks
probable (objective signs) Goodell sign (softening of cervix)
Chadwick sign (cervix is blue/purple)
Hegar’s sign (softening of lower uterine
segment) Uterine enlargement
Braxton Hicks contractions (may be palpated by 28 weeks)
Uterine soufflé (soft blowing sound due to blood pulsating through
the placenta) Integumentary pigment changes
Ballottement, fetal outline definable, positive pregnancy test (could be
hydatidiform mole, choriocarcinoma, increased pituitary gonadotropins at
menopause)
positive (diagnostic signs) Fetal heart rate auscultated by fetoscope at 17–20 weeks or by
Doppler at 10–12 weeks
Palpable fetal outline and fetal movement after 20 weeks
Visualization of fetus with cardiac activity by ultrasound (fetal parts visible by 8 weeks)
Pregnancy and fundal height measurement
Signs of pregnancy (presumptive, probable, positive)
Pregnancy and fundal height measurement As pregnancy progresses, the
fundus rises out of the pelvis (Figure 29-1). At 12 weeks’ gestation, the
fundus is located at the level of the symphysis pubis. By week 16, it rises to
midway between symphysis pubis and the umbilicus. By 20 weeks’
gestation, the fundus is typically at the same height as the umbilicus. Until
term, the fundus enlarges approximately 1 cm per week. As the time for
birth approaches, the fundal height drops slightly. This process, which is
commonly called lightening, occurs for a woman who is a primigravida
around 38 weeks’ gestation but may not occur for the woman who is a
multigravida until she goes into labor
,Naegele’s rule
Add seven days to the first day of your LMP and then subtract three months.
For example, if your LMP was November 1, 2017: Add seven days (November
8, 2017). Subtract three months (August 8, 2017).
The EDD is calculated by adding seven days to the first day of the last menstrual period,
subtracting three months and adding one year.
This formula is known as Naegele's Rule. For example, if the patient's last menstrual
period, LMP, was on August 10, 2019, the EDD would be calculated as follows. LMP
equals August 10, 2019 plus seven days. August 17, 2019, minus three months. May
17, 2019 plus one year and that equals May 17, 2020.
Hematological changes during pregnancy
During pregnancy, the heart is displaced upward and to the left within the
chest cavity by the gravid uterus’s pressure on the diaphragm. As
pregnancy progresses, the risk for inferior vena cava and aortic compression
leading to supine hypotension increases when the woman lies in a supine
position. To avoid hypotension and potential syncope, the woman should be
advised to lie in a left lateral position. Hemodynamic changes and anatomic
changes also may alter vital signs in the pregnant woman (Table 29-2).
,Cardiac output in pregnancy increases by 30% to 50% over that in women
who are not pregnant (Blackburn, 2013; Ouziunian & Elkayam, 2012).
This increase peaks in the early third trimester and is maintained until
birth. Half of the total increase in cardiac output, however, occurs by the
eighth week of pregnancy (Blackburn, 2013). Therefore, women with
cardiac disease may become symptomatic during the first trimester. Stroke
volume is also increased during pregnancy by 20% to 30%. These increases
in cardiac output and stroke volume allow for the 30% increase in oxygen
consumption observed during pregnancy.
TABLE 29-2 Vital Sign Changes in Pregnancy
Vital Sign Changes in Pregnancy Measurement Alterations in
Pregnancy
Heart rate Volume of the first heart sound Palpate the maternal pulse when
and heart may be increased with splitting. auscultating the fetal heart rate to
sounds Third heart sound may be be able to distinguish between the
detected. two.
Systolic murmurs may be detected.
Increases by 15–20 beats/min by
32 weeks’ gestation.
Respiratory Increases by 1–2 breaths/min None
rate
BP First trimester: same as Use of an automated cuff may
prepregnancy values improve accuracy of
Second trimester: systolic BP measurement, as some pregnant
decreases by 2–8 mm Hg and women do not have a fifth
diastolic BP decreases by 5–15 Korotkoff sound.
mm Hg due to peripheral vascular Systolic and diastolic BP may
resistance be 16 mm Hg higher when
Third trimester: gradually returns to taken while the woman is
prepregnancy values sitting.
BP readings may decrease in the
maternal left lateral position.
Abbreviation: BP, blood pressure.
Data from Jarvis, C. (2016). Physical examination and health assessment (7th ed.). St. Louis, MO:
Saunders Elsevier; Ouziunian, J., & Elkayam, U. (2012). Physiologic changes during normal
pregnancy and delivery. Cardiology Clinics, 30, 317–329; Tan, E., & Tan, E. (2013). Alterations in
physiology and anatomy during pregnancy. Best Practice & Research Clinical Obstetrics &
Gynaecology, 27, 791–802.
During pregnancy, blood volume increases by 30% to 50%, or 1,100 to
1,600 mL (Ouziunian & Elkayam, 2012), and peaks at 30 to 34 weeks’
gestation. The increase in blood volume improves blood flow to the vital
organs and protects against excessive blood loss during birth. Fetal
growth during pregnancy and newborn weight are correlated with the
degree of blood volume expansion.
Of the blood volume expansion occurring during pregnancy, 75% is
considered to be plasma (King et al., 2015). There is also a slight increase
in red blood cell volume
, (RBC). The blood volume changes result in hemodilution, which leads to a
state of physiologic anemia during pregnancy. As the RBC volume increases,
iron demands also increase. Leukocytosis occurs in pregnancy, with white
blood cell counts increasing to as much as 14,000 to 17,000 cells per mm3
of blood (Table 29-3). Clotting factors increase as well, creating a risk for
clotting events during pregnancy.
Systemic vascular resistance is reduced due to the effects of progesterone,
prostaglandins, estrogen, and prolactin. This lowered systemic vascular
resistance, in combination with inferior vena cava compression, is partly
responsible for the dependent edema that occurs in pregnancy. Epulis of
pregnancy, or hypertrophy of the gums accompanied by bleeding, may also
occur and is due to decreased vascular resistance and increase in the
growth of capillaries during pregnancy (Jarvis, 2016).
Indications and contraindications for prescribing combined estrogen
vs. progesterone-only birth control
Progestin-only contraceptives are used continuously; there is no hormone-
free interval, as occurs with combined methods. These contraceptive
methods have minimal effects on coagulation factors, blood pressure, or lipid
levels and are generally considered safer for women who have
contraindications to estrogen, such as cardiovascular risk factors, migraine
with aura, or a history of VTE. In spite of this belief, the product labeling for
some progestin-only products mimics the labeling for products containing
estrogen.
The U.S. Medical Eligibility Criteria for Contraceptive Use (CDC, 2010;
see Appendix 11-A) can be used to identify appropriate candidates for
progestin- only contraception.
Progestin-only contraceptives do not provide the same cycle control as
methods containing estrogen, and unscheduled bleeding is common with all
progestin-only methods. Typically, unscheduled bleeding occurs most
frequently during the first 6 months of method use, with a substantial
number of users becoming amenorrheic by 12 months of use (Hubacher,
Lopez, Steiner, & Dorflinger, 2009). Overall blood loss decreases over
time, making progestin-only methods protective against iron- deficiency
anemia. With appropriate counseling, many women see amenorrhea as a
benefit of these methods.
All progestin-only methods are likely to improve menstrual symptoms,
including dysmenorrhea, menorrhagia, premenstrual syndrome, and anemia
(Burke, 2011). The thickening of cervical mucus seen with progestin
methods is protective against PID. Progestin-only contraceptives include the
progestin-only pill (POP), an injection, an implant, and three progestin-
containing intrauterine devices. The implant and devices are covered in the
section on long-acting reversible contraception.
The U.S. Medical Eligibility Criteria for Contraceptive Use (CDC, 2010) is a
comprehensive, evidence-based guide for determining whether women
have relative or absolute contraindications to contraceptive methods. The
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