Question

1. Explain the normal processes of childbirth: premonitory signs, mechanisms of birth, and stages and phases of labor.
2. Explain how false labor differs from true labor.
3. Describe environmental hazards that may adversely affect the outcome of pregnancy.

Answer 1

Answer :

1.Premonitory signs :

The series of changes happens in the utrus and cervix to facilitate onset of labor and accomplish childbirth. These premonitory signs and symptoms begings approximately 2 to 3 weeks prior to onset of labor in primigravida but just few days prior in multigravida.

• Lightening :Sensation of decreased abdominal distention and relief due to the descent of the fetal head into the pelvic inlet 2-3 weeks prior to onset of labor.
• Releaf from breathlessness: As the fetal head descent, the pressure on the pulmonary diaphragm decreases, giving relief from breathlessness.
• Increased uterine contractions : Under the influence of hormonal changes and prostaglandins, the frequency, intensity and duration of false labor pain increases and they become more regular. Subsequently giving way to onset of true labor.
• Discomfort and pain in lower abdomen, pelvis, lower backa and inner thigh.
• Difficulty in walking
• increased frequency of urine
• blood mixed mucus discharge from vagina.

Mechanism of labor :

Steps of mechanism of labor include :

• Head enters the brim through diameter (70 %) and to a lesser extent through one of the oblique diameter.
• Position : occipito lateral or oblique occipitoanterior(left > right )

The principal movements are :

• Engagement : The sensation that a feels when the lowermost part of the fetus descent and is engaged in the mother's pelvis, an event that typically occurs 2 to 3 weeks before labor begins.
• Descent : The downward passage of the presenting part through the pelvis. This occurs intermittently with contractions.
• flexion : during flexion uterine contractions push the fetus downward against the cervix.
• internal rotation : is the occiput occurs because in the normal delivery where the head is fully flexed the occiput is the most dependant part of the fetus and reaches the pelvic floor first.
• Crowming extension : When the widest diameter of the fetal head successfully negotiates through the narrowest part of the meternal body pelvis , the fetal head is considered to be crowning.
• Restitution
• External rotation
• expulsion of the trunk

Stages of labor:

The first stage : is when the neck of womb (cervix) opens to 10 cm dialation. During this time contraction, 'show', and braking of waters takes place.

The second stage of labor :The stage of labor begins when thebirth canal is fully dialated and the baby's head moves down out of the uterus and into the birth   birth canal.

The third stage of labor the placenta : The final stage of the labor is delivary of placenta  

2. True labor :

Contractions come and get closer together over time, lasting about 30 to 70 seconds each. They continue regardless of movement or resting. They progressively get stronger. Usually they start in the back and move to the front.

False labor :

Before "true" labor begings, might have "false" labor pains, also known as Braxton Hicks contractions. These irregular utrine contractions are perfectly normal and might start to occur from fourth month of pregnency.

One differance between true and false labor is that false labor (sometimes called Braxton-Hicks contractions) will not dialate cervix. The contractions may come at regular intervals but they will not increase in strength or get closer together. For instance, they may be 5 minutes apart for hours but not change cervix at all.

Signs of false labor :

• Contractions will feel better while walking
• Contractions may stay the same strength
• Contractions may stay the same interval for long periods of time.
• False labor is felt generally only in the front
• False labor does not have bloody show associated with it

Signs of true labor :

• Contractions will increase in strength while walking
• contractions will get stronger in intensity over time
• contractions will gradually become closure together
• contractions will start in in back and move to the front.
• Bloody show may be present with true labor.

Time of the contractions for the start of one to the start of the next and keep list of each one. Write down how long each contraction lasts. This will help to know if it is time to go to hospital.

3. Various epidemiological studies have suggested associations between environmental exposure such as :

• smoking
• vedio display terminals : it iss do not emit ionizing radiations, but they do emit electromagnetic radiations. Their use has not been associated with adverse pregnency out come or to any teratogenic effects. Exampl :daily exposure to mobile phones, heated beds, electric blankets and health professional using diagnostic and therapeutic devices.
• anesthetic gases
• antineoplastic drugs and exposure lead :exposure to ionizing radiation during periconceptional period and during erly gestation has been associated with congenital deffects and risk of childhood cancer.
• seleniuma nd inorganic mercury
• cigarette smoking during pregnency : Mothers who smoke during pregnancy are twice as likely to give birth to low birth weight infants (weight average 250 to 250 gm less than infants born to non-smoking mothers). Inutero , nicotine targets the fetal nicotinic cetylcholine recptors in the brain , to change , to change the pattern cell proliferation and differanciation.
• Air pollusion : It has been associated with congenital birth defects, as well as with low birth weight and intrauterine growth restriction.
• pesticide exposure : Pregnent women working in the agricultural fields , landscape artists are at risk for pesticide exposure . This leads to spontaneous miscarriages , low birth weight and preterm delivery in green houseworkers.Other potential effects of exposure include infertility, reduced fecundity in women of reproductive age group.
• stress : have also been associated with low birth weight and preterm delivery.