Alcohol use during pregnancy was previously listed as a risk factor, but is discredited by this article. Classification
Traditionally, four grades of placenta previa were used, but it is now more common to simply differentiate between "major" and "minor cases. Other than that placenta previa can be also classified as:
Complete: When the placenta completely covers the cervix
Partial: When the placenta partially covers the cervix
Marginal: When the placenta ends near the edge of the cervix, about 2 cm from the internal cervical os

Diagnosis
History may reveal antepartum hemorrhage. Abdominal examination usually finds the uterus non-tender, soft and relaxed. Leopolds maneuvers may find the fetus in an oblique or breech position or lying transverse as a result of the abnormal position of the placenta. Malpresentation is found in about 35% cases. Vaginal examination is avoided in known cases of placenta previa. Confirmatory
Previa can be confirmed with an ultrasound. Transvaginal ultrasound has superior accuracy as compared to transabdominal one, thus allowing measurement of distance between placenta and cervical os. This has rendered traditional classification of placenta previa obsolete.False positives may be due to following reasons:
Overfilled bladder compressing lower uterine segment
Myometrial contraction simulating placental tissue in abnormally low location
Early pregnancy low position, which in third trimester may be entirely normal due to differential growth of the uterus.In such cases, repeat scanning is done after an interval of 15–30 minutes. In parts of the world where ultrasound is unavailable, it is not uncommon to confirm the diagnosis with an examination in the surgical theatre.
Nicardipine (Cardene) is a medication used to treat high blood pressure and angina. It belongs to the dihydropyridine class of calcium channel blockers. It is also used for Raynauds phenomenon. It is available in by mouth and intravenous formulations. It has been used in percutaneous coronary intervention. Nicardipine has been used as an alternative to sodium nitroprusside, especially because sodium nitroprusside is light sensitive and a fresh solution must be prepared. Its mechanism of action and clinical effects closely resemble those of nifedipine and the other dihydropyridines (amlodipine, felodipine), except that nicardipine is more selective for cerebral and coronary blood vessels. Nicardipine also has a longer half-life than nifedipine. Nicardipine was approved by the FDA in December 1988. The patent for both Cardene and Cardene SR expired in October 1995.It was patented in 1973 and approved for medical use in 1981. See also
Calcium channel blocker toxicity


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