In about half the patients who bleed antenatally you never find a cause. When you do find one it may be: (1) Obvious placental abruption (mild, moderate, or severe). (2) Placenta praevia (Grades One, Two, Three, or Four). (3) A variety of usually harmless lesions of the lower genital tract. The first two causes are much the most dangerous ones, but fortunately they are both about equally uncommon. An important problem in the antenatal clinic is the patient with a small bleed: ''Has she got placenta praevia, or is it going to remain unexplained?''
BLEEDING AFTER THE 28TH WEEK Admit her, keep her in bed, and observe her carefully. Record all the blood she loses. Measure and record her pulse, blood pressure, and haemoglobin.
Decide how much blood she has lost. She may be: (1) An emergency with severe bleeding (500 ml or more), or in shock, or in labour. (2) A non-emergency with none of these things.
Resuscitation may need to start immediately. Take blood for grouping and cross-matching, and make sure that there are always 2 units of blood cross-matched for her.
Examine her, but don't do a vaginal examination with your fingers! Ask yourself three questions: (1) Has her uterus ruptured (18.17) due to obstructed labour? (2) Has she ruptured the scar (18.14) from a previous Caesarean section? Both these are uncommon causes of vaginal bleeding during pregnancy or labour. (2) How likely is she to have placenta praevia? (see below)
Decide the probable duration of her pregnancy (don't use the surfactant test (19.2), because the amniocentesis needle may go through a low-lying placenta). Record the position, presentation, and lie of the baby. Feel for rhythmical contractions. Listen to his heart.
CAUTION! If you find an abnormal lie, don't try to correct it.
Test her urine for protein. This is worth doing even though interpreting the result may be difficult.
DIAGNOSIS. Assess the probabilities like this:
Suggesting placenta praevia[md](1) Bright red painless bleeding which can be anything from mild to severe, especially after 32 weeks, and tends to stop and start again. (2) A soft non-tender uterus that relaxes between contractions. (3) The fetal heart can be heard. (4) Shock is proportional to the blood she has lost. (5) The presenting part is higher than expected, and an unstable lie or an abnormal one are common. Suspect placenta praevia if you find a high head or a breech, a head or breech overlapping her symphysis by more than two finger widths, or a transverse lie. Placenta praevia is unlikely (but not impossible), if the head or breech are in easy contact with her symphysis, and do not overlap it. You can only be sure that she has not got placenta praevia, if the head or the breech are deeply engaged in her pelvis. If placenta praevia is likely, see Section 16.12.
Suggesting abruption[md](1) Painful bleeding which is slight to moderate. (2) The presenting part is not higher than you expect, and the lie is usually stable. (3) A tense, tender, woody-hard uterus with poorly defined fetal parts. (4) An absent fetal heart. (5) Shock which is worse than you would expect from the blood she has lost vaginally. (6) Constant lower abdominal pain. (7) Loss of fetal movements. If abruption is likely, see Section 16.13.
CAUTION ! Beware of diagnosing abruption in a patient who has had a previous Caesarean section; rupture of her uterus is much more likely, even if she has not been in labour for long.
Suggesting a heavy show[md](1) There is less than 10 ml of blood. (2) She bleeds with contractions. (3) Blood is usually mixed with mucus. (4) Bleeding stops when her membranes rupture.
Suggesting rupture of her uterus[md]See Section 18.17.
If she does not have an obvious abruption or placenta praevia, and is not in labour, do a speculum examination.
SPECULUM EXAMINATION. Do this to see where the blood is coming from, and to diagnose the incidental causes of bleeding. Do it in the labour ward in the lithotomy position in a good light. It is not easy, and can precipitate bleeding if you do it roughly. Even poking around to find the cervix can cause bleeding if she has placenta praevia. Pass a sterile speculum.
CAUTION ! Don't examine her vaginally with your fingers. If she does have a placenta praevia, you may cause massive bleeding. Use gentle speculum examination only.
Look for: (1) Cervical erosions. (2) Cervical polypi. (3) Vaginitis. (4) Carcinoma of her cervix. (5) Varicose veins (rare). (6) Decidua in her upper endocervix.
If she has placenta praevia (hopefully most unlikely, since you are examining her in the labour ward), you may see[md]a normal cervix, a haemorrhagic mucous plug, a blood clot in her external os, active bleeding from her cervix, or an open cervix with placental tissue peeping out of it. If you mistakenly do a digital examination, there will be a boggy feeling of placenta in front of the baby's head, followed by torrential bleeding as you remove your finger!
If she has abruption, you will see blood coming out of her cervix (if you mistakenly do a digital examination, you don't feel placenta).
If she has trichomoniasis (red vaginal wall and a pale green frothy discharge), treat her and her sexual partner at the same time (M 29.6).
If she has cervical erosions, they will usually heal after delivery and need no specific treatment. Treat any associated trichomoniasis. They seldom cause more than staining of her underwear or spotting, which may be related to sex.
If she has vulval varicosities, local pressure will probably stop it. If necessary, insert a suture. Varicosities sometimes occur at the vulva or introitus of older multips and occasionally bleed.
If she has a cervical polyp, don't twist it off during pregnancy: it may bleed severely. Leave it alone, and deal with it after delivery (20-5).
If she has carcinoma of her cervix, and is in labour, section her. If the lesion is large, the classical operation is better.
If you find an incidental cause of bleeding, she can get up and go home, if appropriate, depending on the cause. However, finding an incidental cause (such as a small polyp) does not prevent her from also having a placenta praevia, so beware! Does the incidental cause look as if it could have caused the bleeding she describes?
If you are not sure what she has, she will probably only have mild bleeding, but you will be wise to assume that she might have placenta praevia.
Fig. 16-9 ANTEPARTUM BLEEDING. The three types of abruption, revealed, concealed, and mixed, and the four types of placenta praevia. From Munro Kerr's ''Operative obstetrics' (7th edn. edited by Chassar Moir), Figs. 30,1 and 30,2. Balli[gr]ere Tindall, with kind permission.